Total Synthesis @TotalSynthesis
@SoufianTibouti thinks Nature is the ultimate chemist. linkedin.com/in/soufiantibo… Ottawa, ON Joined August 2013-
Tweets2K
-
Followers17K
-
Following1K
-
Likes8K
#TotalSynthesis of (−)-Neocucurbol C Enabled by Pattern Recognition and MHAT Cyclization by Li-Ping Zhong, Cyrus Gudeman, Jingsong Zhen (@jzhe265), Oshani A. Wanasinghe, Jacob Hellmig, Michael J. E. Collins, John Bacsa, Alexander Adibekian, @MingjiDai at @EmoryChem in @J_A_C_S…
Diastereo-, Enantio-, and Chemoselective Sequential Allylations of N,N’-Alloc 3, 3’-Dimeric 2-Oxindoles: Formal #TotalSynthesis of (-)-Idiospermuline by @Kundanchem14, Avishek Roy, @debabrata1debu, @ShyamalPranay, @arindamkhatua, and @AlakeshBisai @AB_Group_IISER at @iiserbhopal…
#TotalSynthesis and Structure Determination of Mycapolyol E Using Iterative Homologation of Boronic Esters by @sheenagh_aiken, @DylanRigby6, @fiorito_daniele, Malcolm R. P. George, Simon Wübbolt, Adam Noble, and @VarinderAggar11 @AggarwalLab at @BristolChem in…
Enantioselective #TotalSynthesis of Bipolarolides A and B by Yufei Liu, Ke Sun, Qi Wei, Jin Chen, Shengling Sun, Yaxin Li, Zhongkai Feng, Yingying Guo, and Zhaohong Lu in @J_A_C_S pubs.acs.org/doi/10.1021/ja…
#TotalSynthesis of Paxdaphnine A and Daphlongamine B via an Aza-Prins Cyclization Strategy by Lu Ren, Zhaohong Lu, Dimin Wu, Mingchen Ma, and Ang Li at Shanghai Institute of Organic Chemistry in @J_A_C_S pubs.acs.org/doi/10.1021/ja…
The Enantioselective #TotalSynthesis of (+)-3-Ketobrassicicene W and (−)-Alterbrassicicene B by Weston C. Bonnet, Noah J. Sims, Joseph P. Tuccinardi, Alexis N. Donahue, Danielle M. Lawson, and John L. Wood (@JohnWoodGroup) at @BaylorCBC in @JOC_OL pubs.acs.org/doi/10.1021/ac…
Convergent #TotalSynthesis of Erchinines A and B and Their C20 Epimers by Yong Sun Cho, Joseph P. Tuccinardi, and John L. Wood @JohnWoodGroup at @BaylorCBC in @J_A_C_S pubs.acs.org/doi/10.1021/ja…
An Expedient #Synthesis of the Antimitotic Natural Products Sarcodictyin and Eleutherobin, and Carbohydrate Analogues by Daniel Driedger, Anthony Fers-Lidou, Megan Schroeder, Ingrid Elisia, Gerald Krystal, and Robert Britton @BrittonLab at @SFUChemistry in @J_A_C_S…
#TotalSynthesis of (+)-Herpotrichones A–C by Yoojin Lee, Taewan Kim, Geon Kim, Dongwook Kim, and Sunkyu Han (@hanpisa) at @kaistpr in @J_A_C_S pubs.acs.org/doi/10.1021/ja…
#TotalSynthesis of (−)-Enigmazole A by the Macrocyclization/Transannular Pyran Cyclization Strategy: Application to Structure–Activity Relationship Investigations by Kyoya Ohyama, Taisei Masuda, Keita Sakamoto, Atsushi Yoshimura, Kyoko Tatsumoto, Keisuke Murata, and Haruhiko…
#Synthetic Studies toward the Aphidicolin Family of Diterpenoid Natural Products by Jack Hayward Cooke, Safaa Jamshed, and Richmond Sarpong @SarpongGroup at @UCB_Chemistry in @JOC_OL pubs.acs.org/doi/10.1021/ac…
Concise #Synthesis of Fostriecin and Analogs through Late-Stage #Chemoenzymatic Installation of Their Key Pharmacophores by Yanlong Jiang, Xuerong Yu, and Hans Renata (@hanzyduzit) at @RiceChemistry in @J_A_C_S pubs.acs.org/doi/10.1021/ja…
Stereodivergent #Synthesis of Perhydrobenz[e]indene Terpenoids by Cheng Yang, Christopher J. Huck, @YaroslavBoyko4, Shang Ning, Uroš Vezonik, Alexander S. Shved, Scott E. Denmark, Binh Khanh Mai, David Sarlah @SarlahLab at @RiceChemistry in @J_A_C_S pubs.acs.org/doi/10.1021/ja…
#TotalSynthesis of Daphenylline via Diels–Alder Cycloaddition and Rhodium-Catalyzed C–H Alkynylation by Wei Chen, Aohang Liu, Jinwei Huang, Pengfei Yu, Huaxuan Zhang, Huilin Li, Xingang Xie, Gaoyuan Zhao, and Xuegong She in @JOC_OL pubs.acs.org/doi/10.1021/ac…
Asymmetric #Synthesis of Unnatural (−)-Gracilamine by Maxime Denis and Sylvain Canesi at @UQAM in @JOC_OL pubs.acs.org/doi/10.1021/ac…

J. Am. Chem. Soc. @J_A_C_S
185K Followers 10K Following Research, news, and information from the Journal of the American Chemical Society.
EurJOC @EurJOC
22K Followers 2K Following EurJOC brings you the latest developments in organic chemistry. #EurJOC We have changed our X account. Find our latest updates on @ChemEurope.
Chemical Science @ChemicalScience
100K Followers 4K Following This account has been archived. Stay connected with us on LinkedIn, BlueSky and Facebook.
Organic Chemistry Por... @organic_portal
11K Followers 269 Following The Organic Chemistry Portal offers an overview of recent topics, interesting reactions, and information on important chemicals for organic chemists
MaulideGroup @MaulideLab
17K Followers 455 Following Research group based in Vienna. Organic synthesis and methodology
Nick Chiappini 🏳�... @ndchiappini
12K Followers 3K Following Lover of weird rxns, reactive intermediates, and equitable sci. Asst Prof at UNCW. Queer AF. Ligand appreciator.
60% Water By Mass @MoleculesGoHard
7K Followers 513 Following The tradition of all the dead generations weighs like a nightmare on the brain of the living Ⓥ
Waser Group @LcsoLab
14K Followers 7K Following Driven by Passion for Chemistry Organic Chemistry Lab @EPFL_CHEM_Tweet @EPFL_en @NCCR_Catalysis @SNE_ChemBio
Chinese Chemical Lett... @ChinChemLett
12K Followers 9K Following A leading chemistry journal by @ChineseChemSoc covering the whole field of chemistry. IF = 9.4 (2023). Tweets by @Zhichang_Liu on behalf of the editorial office
⌬ anna davis! ⌬ @radscientist_
10K Followers 2K Following postdoc @lovingerlab, phd @hilinskigroup - cycloaddition enthusiast, echem enjoyer, computational chemist wannabe, long-suffering horse girl 🩷💜💙
Yulab @YulabJin
13K Followers 528 Following breaking one CH bond per day...keeping headaches away...
Sarpong Group @SarpongGroup
9K Followers 436 Following Student-run twitter account for the Sarpong group at UC-Berkeley.
Nature Synthesis @NatureSynthesis
20K Followers 10K Following A synthesis-oriented chemistry & materials science journal from @SpringerNature. Tweets by the editors @PSeavill @DrARGroves & @drtwest
Song Lin Lab @SongLinLab
10K Followers 917 Following Electrifying organic chemistry since 2016 | Cornell University | For group updates, find us on LinkedIn!
Synthesis Workshop @MatthewHorwitz1
8K Followers 860 Following Synthesis Workshop is a video podcast exploring the frontiers of synthetic organic chemistry created by Matt Horwitz, Ph.D. https://t.co/iB4pKXqHuX
Dr. Ortiz, Process Ch... @KCGOrtiz
4K Followers 4K Following Gardening, Gundams, and Games. Big Critical Role & Kinda Funny Fan. PhD, Auburn '24 | BSc, TAMU '16 | Dog/Cat Dad | Big Wife Guy (@racheleortego).
Jake Yeston @JakeYeston
9K Followers 3K Following Editor @sciencemagazine, left this God-forsaken site for bluer pastures (https://t.co/EPRofYnUOm)
NaOH Bartfield 🧪 @NaOHBartfield
7K Followers 2K Following Ph.D. Candidate @YaleChem (@HerzonLab) - Frederich Lab Alum (@fsuresearch) - NSF Fellow - #CASFutureLeaders 2024 - Complex Molecule Synthesis - ✡︎
Dirk H. Trauner @DirkTrauner
16K Followers 12K Following Penn Integrates Knowledge Professor, Natural Product Aficionado, Photopharmacologist, Fox Terrierist, and Unfulfilled Architect. #firstgen
Alex Speed @awhspeed
10K Followers 4K Following Chemistry Prof locked out from Dalhousie University. Would be doing sustainable organic/main-group chem. Camper, plant hoarder, and Victorian house enthusiast.
Sabrina Taylor @SabrinaTay12932
58 Followers 259 Following
Aman kumar Indora @AmankumarIndor1
0 Followers 27 Following
Yusuke NAKAMURA @YusukeNAKA13637
0 Followers 2 Following
Ramandeep Kaur @Ph17071Kaur
10 Followers 162 Following Synthetic organic chemist, PhD from IISER Mohali
Narasimha Reddy Mukka... @Nara87180Reddy
0 Followers 23 Following
Marwa Ali @MarwaA52279
2 Followers 227 Following
Sarazzkkk Rez @sarazzkkk53305
0 Followers 80 Following
llcys2 @llcys288471
13 Followers 827 Following
Cao Shen @Zichen3e
1 Followers 35 Following Ph.D with Biao Yu and Xiaheng Zhang in SIOC & HIAS, Chinese Academy of Science; Post-Doctoral Fellow with Lu Jiong in National University of Singapore
JJJJJason @JasonChang7776
0 Followers 16 Following
Tin Nguyen Trung @nguyen_tin2901
0 Followers 11 Following
Allen @8o5hfk6B9TOg00R
2 Followers 97 Following
Knight Chemicals @knight_chem
25 Followers 105 Following High-quality building blocks & custom synthesis for drug discovery. Tier 1 delivery. Run by chemists. Built for innovation.
सरोज दु�... @sarojdulal95
297 Followers 948 Following Nepal 🇳🇵 | Biotech | UniNewcastle 🇦🇺 | Natural products Enthusiast | @NeilanBGGM | Kathmandu University Microbes are Wonder!!
Domesticated Brain @rasangarocks
62K Followers 66K Following This is the official twitter account for web site called Domesticated Brain. We are sharing various kinds of #computer #tutorials and latest #technology news.
Michaela Buzikova @itsmibuzi
2 Followers 18 Following
Nacho @nachirulo21
355 Followers 3K Following
KISOMO TV @Kisomotvtz
1 Followers 10 Following Kituo cha Mambo ya Sunnah, Mawaidha na Quran Subscribe YouTube channel yetu 👇
Subhajit Ghosh @ghoshsubha06
1 Followers 61 Following
Mainak Chatterjee @mainak8902
1 Followers 204 Following
Calvin Hawe @calvin_hawe
135 Followers 2K Following Chemistry Research Associate @OctantBio; Former Biochemistry Student at Notre Dame @NDscience Substack Blog: https://t.co/17S0GIfNnY
Alex Zhurakovskyi �... @zhorakovsky
1K Followers 181 Following Process chemist at Pharmaron UK. Developer of Chemistry Reference Resolver: https://t.co/iPZQ3D1quH.
Tyler @trough74
146 Followers 403 Following
Seal. @Seal23233689
0 Followers 6 Following
Tomohiro Nakahama/中... @nakatomo_org
32 Followers 212 Following 中濱智弘/Okayama Univ. D1 (Prof. Seiji Suga)/Organic electrochemisry
無線 @Z5Y2F8V1N7J3X6K
96 Followers 413 Following
ろっぴい @KG7xGqW0ITwn4dp
0 Followers 20 Following
Dr. TAVINDER SINGH @TAVINDE82839435
11 Followers 153 Following
M. Fadhlirrahman Lati... @Fadhlirrah97738
4 Followers 450 Following
Mayursinh Zala @MAYURSINH_PHD
2 Followers 63 Following #Actively looking for Postdoctoral Position in field of Organic Chemistry Ph.D. & M.Phil. -(Synthetic Medicinal Chemistry),https://t.co/5AIP88fySf. (Organic Che
SUNASA @SunasaP5735
6 Followers 158 Following
PHORN SIPHEANG @phorn_sipheang
27 Followers 309 Following
buddhahands1 @buddhahands1
66 Followers 741 Following I am a CranioSacral Therapist, SomatoEmotional Release Therapist, Divine Reiki Master, ThetaHealer & Spiritual Channel. Call & schedule 858 245-2654
Kyle Nagasawa @kyle_nagasawa
0 Followers 3 Following
lily owen @owen_lily49974
115 Followers 3K Following
Kudakwashe Mutanga @Kudakwashe40181
12 Followers 852 Following Everything is always in motion #chemicaldataanalyst
Glejdi @Glejdi48394
21 Followers 619 Following
keepcalm @blackbelt06
0 Followers 643 Following
Satan Sarinda @satansarinda01
1 Followers 77 Following
Ashish Kumar @kr31ashish
8 Followers 488 Following
Fitsum Lemilemu @LemilemuFG
0 Followers 47 Following
Soso Ibn Ben Bakr Rus... @AdArmaCives
1K Followers 4K Following Caucasian. wrightwinger. Georgian Legionaire. Matematician. War veteran. RUST/SCALA/HASKELL/R. Weapons, NRA!
Angewandte Chemie @angew_chem
111K Followers 3K Following Angewandte Chemie, a journal of the German Chemical Society (GDCh, @GDCh_aktuell) - a leading journal in #chemistry published by @WileyVCH in @Weinheim
J. Am. Chem. Soc. @J_A_C_S
185K Followers 10K Following Research, news, and information from the Journal of the American Chemical Society.
J Org Chem/Org Lett @JOC_OL
53K Followers 531 Following JOC and OL serve as the leading international forums for communicating important research in all branches of the theory and practice of organic chemistry.
Boron-Chem-Research @Boron_Chemistry
24K Followers 0 Following Latest research in organoboron chemistry
EurJOC @EurJOC
22K Followers 2K Following EurJOC brings you the latest developments in organic chemistry. #EurJOC We have changed our X account. Find our latest updates on @ChemEurope.
Chemical Science @ChemicalScience
100K Followers 4K Following This account has been archived. Stay connected with us on LinkedIn, BlueSky and Facebook.
Organic Chemistry Por... @organic_portal
11K Followers 269 Following The Organic Chemistry Portal offers an overview of recent topics, interesting reactions, and information on important chemicals for organic chemists
MaulideGroup @MaulideLab
17K Followers 455 Following Research group based in Vienna. Organic synthesis and methodology
Waser Group @LcsoLab
14K Followers 7K Following Driven by Passion for Chemistry Organic Chemistry Lab @EPFL_CHEM_Tweet @EPFL_en @NCCR_Catalysis @SNE_ChemBio
Chinese Chemical Lett... @ChinChemLett
12K Followers 9K Following A leading chemistry journal by @ChineseChemSoc covering the whole field of chemistry. IF = 9.4 (2023). Tweets by @Zhichang_Liu on behalf of the editorial office
⌬ anna davis! ⌬ @radscientist_
10K Followers 2K Following postdoc @lovingerlab, phd @hilinskigroup - cycloaddition enthusiast, echem enjoyer, computational chemist wannabe, long-suffering horse girl 🩷💜💙
Chemistry at Thieme @thiemechemistry
11K Followers 1K Following Publishing content feat. recent developments in the field of #organicsynthesis, #organicmaterials, #medchem & #greenchemistry. 👩🏻🔬👨🏻🔬
Yulab @YulabJin
13K Followers 528 Following breaking one CH bond per day...keeping headaches away...
Sarpong Group @SarpongGroup
9K Followers 436 Following Student-run twitter account for the Sarpong group at UC-Berkeley.
Engle Lab @EngleLab
11K Followers 208 Following catalysis, reaction discovery, and samoyed sled racing @scrippsresearch. views our own.
Nature Synthesis @NatureSynthesis
20K Followers 10K Following A synthesis-oriented chemistry & materials science journal from @SpringerNature. Tweets by the editors @PSeavill @DrARGroves & @drtwest
AggarwalLab @AggarwalLab
10K Followers 195 Following Synthetic organic chemistry group focused on the incorporation, homologation and functionalisation of organoboron compounds. Group ran account.
ChemEurJ: Chemistry -... @ChemEurJ
60K Followers 963 Following A Multidisciplinary Chemistry Journal - The heart of the Chemistry Europe @ChemEurope portfolio (https://t.co/42j8T8Mpwl)
Song Lin Lab @SongLinLab
10K Followers 917 Following Electrifying organic chemistry since 2016 | Cornell University | For group updates, find us on LinkedIn!
MChangGroup @MChangGroup
1K Followers 128 Following Student-run account of the Michelle Chang Lab at Princeton || Synthetic Biology || Metabolic Engineering || Biocatalysis || Find us at https://t.co/vY70QdSAlr
Gilliard Group @gilliardgroup
5K Followers 186 Following Main-Group | Organometallic Chemistry | Luminescent Materials Research Group @MIT led by @rjgilliard. *Account managed by members of the group.
LambertGroupODU @LambertGroupODU
219 Followers 420 Following Our group is interested in synthetic organic chemistry, computational chemistry, and natural product synthesis and highlight our latest efforts here.
Maxime Hourtoule @HourtouleMaxime
86 Followers 244 Following Post-doc with @aztul in Göttingen 🇩🇪, PhD with @lab_sophy in Strasbourg 🇨🇵
Reem Al-Ahmad | ري�... @reemalahmadd
236 Followers 506 Following T32 NIH Fellow | Synthesis Workshop editor | PhD candidate in Prof. Mingji Dai’s lab | @umich alumna’ 21
Chemistry Edinburgh @EdinburghChem
6K Followers 1K Following News, research, events and stories from the School of Chemistry, @EdinburghUni 🧪
Johnson Lab UNC @JohnsonGroup
2K Followers 231 Following Student-run Twitter page for Jeffrey Johnson’s lab at UNC Chapel Hill | Cutting-edge Catalysis and Natural Products Synthesis
Weix Group @weixgroup
5K Followers 100 Following Weix Group at UW-Madison. Primarily student run, with the occasional DJW tweet. Mostly group news. @weixgroup.bsky.social
İsmail Yaşar Kökç... @kokculer
167 Followers 295 Following 11:88, 8:17-18, 9:50-51 | @BilkentUniv and #LINO22 alum
Àlex Martí Zaragoza @Alex_Marti_Z
108 Followers 247 Following Chemist 🧑🏼🔬 PhD in organic chemistry @Echavarren_Lab
Echavarren Lab @Echavarren_Lab
3K Followers 867 Following Organometallic chemistry for health and material science applications @ICIQchem (@iCERCA centre, member of @_BIST and @SOMM_alliance)
Rajib Kr Goswami Tota... @GoswamiLab_IACS
667 Followers 742 Following Account run by students doing Asymmetric Total Synthesis of Bioactive Natural Products || Housed at @iacskolkata 🇮🇳 || Headed by @RajibTotally
Timothy Vanden Berg @TVandenBergAus
1K Followers 2K Following Chemist. Total synthesis & med chem | electronic structure calculations & x-ray crystallography on the side | #ozchem
Deng Lab@NKU @NKU_Jun_Deng
9 Followers 28 Following
John L. Wood @JohnWoodGroup
2K Followers 80 Following We are a group of organic chemists interested in natural products synthesis. We highlight here our latest efforts and those of previous W6 members.
Gabe Gomes @gabepgomes
6K Followers 7K Following autonomous science enabler & digital molecular designer | Assistant Professor @CarnegieMellon | h(e/im), views my own
Yuxuan Ye @YuxuanYe2
273 Followers 330 Following Assistant Professor at Westlake University; @Hysterlab postdoc; @BuchwildGroup alumni
Brimble Lab @Brimble_Lab
1K Followers 240 Following Twitter account for Brimble Lab organic synthesis and peptides research at The University of Auckland | student run
Robert Paton @bobbypaton
3K Followers 266 Following Robert Paton | Fixman Ladanyi Professor @csu_chemistry | #compchem | https://t.co/7IGAPM3ISy | @nsf_ccas | @bobbypaton.bsky.social
Piyas Saha @PiyasChem
108 Followers 287 Following A passionate synthetic chemist @TheNewmanLab, CCRI, @uOttawaCHM. I am interested in developing various novel catalytic methods.
Aref vaezghaemi @arefvaezghaemi
28 Followers 161 Following Ph.D. Student at @uOttawaCHM and @TheNewmanLab
PbLab @PbLabUniOvi
338 Followers 162 Following Research group of Pablo Barrio. Really focusing in C(sp3)-H activation, mechanistic studies and riched F(sp3) molecules. Student run twitter.
UZH Chemistry @UZH_Chemistry
3K Followers 100 Following
The Le Group @LeResearchGroup
1K Followers 303 Following A newish research group at York University specializing in reaction & catalyst development. We love fluorine!
QOMSBOC 2024 @qomsboc
32 Followers 70 Following Quebec/Ontario Mini-Symposium for Synthetic and Bioorganic Chemistry QOMSBOC 2024 | November 8–10 | University of Toronto
Diao Lab @diaogroupNYU
2K Followers 313 Following Organic Synthesis. Energy Research. Organometallics. New York University (student-run account)
Rosalie Doerksen Bunn... @rosalieshinwei
107 Followers 170 Following Postdoc @HarvardCCB | PhD @UTChemistry | UPenn alum
Çağrı Özsan @Cagriozsan
408 Followers 930 Following Ph.D. Candidate @TheFreiLab 🧪🦠🧫 MSc in Chemistry 👨🏻🔬 & Molecular Biologist Alumni @itu1773 @kocuniversity @kolemenlab
Abder Amgoune @amgoune_abder
364 Followers 165 Following Prof. Organic chemistry. organomettalic chemistry. Transition metal catalysis, mechanistic studies. Radicals
KoenigChemistry @ChemistryKoenig
5K Followers 72 Following
Princeton Chemistry @PrincetonChem
11K Followers 339 Following Sharing our science & passion for chemistry. Official account of the Chemistry Department @Princeton University. Follow us on Instagram: @PrincetonChem
SYNLETT Journal @synlett_journal
673 Followers 626 Following An international, peer-reviewed Account and Letter journal from Thieme reporting research results and current trends in chemical synthesis.
Garrett Muir @GarrettMuir
116 Followers 231 Following
Morgan Donnard @DonnardMorgan
2K Followers 497 Following Academic Organic Chemist @CNRS @unistra @LIMA_UMR7042. Silicon, alkyne & enamide chemistry. @iupac Fr representative, @DCO_SCF & @alsacescf board member.
Hiroshige OGAWA @hiroshige_ogawa
257 Followers 425 Following Hong Kong University Science and Technology/PhD candidate/Hugh Nakamura lab/Keio MS/Chida-Sato lab
Yuuya Nagata @nagata_yuuya
717 Followers 554 Following Group Leader / Chief Researcher, Autonomous Polymer Design and Discovery Group, National Institute for Materials Science (NIMS)
Vera Demertz @VDemertz
91 Followers 127 Following 🇬🇷 PDRA @uoaofficial | previously PDRA @EdinburghChem | PhD @ximikoauth
ICIQ @ICIQchem
12K Followers 2K Following Institute of Chemical Research of Catalonia is a @iCERCA centre and member of @_BIST. Chemistry that changes society
Ohmiya Lab @OhmiyaLab
2K Followers 312 Following Organic Chemistry, Catalysis, Hirohisa Ohmiya Laboratory, Kyoto University, JAPAN
Aidan Looby @aplooby28
454 Followers 458 Following Ph.D. Candidate at UH | Carrow Group | The SW Pod Host | Widener ‘21 alum
Schoenebeck Group @Schoenebeck_Lab
5K Followers 440 Following
Marc-Etienne Moret | ... @ME_Moret
1K Followers 1K Following Organometallic Chemist – Associate Professor at Utrecht University – views my own
Hypervalent Iodine @HyperIodine
2K Followers 42 Following (Improved!) Feed that aggregates publications about hypervalent iodine from over 200 journals of 15 editors. Contact @CYL_Lab for any question.
Richard Liu @RichrdLiu
1K Followers 181 Following assistant prof @HarvardCCB | formerly postdoc @SwagerGroup, PhD @BuchwildGroup | chemicals enthusiast
Sakshi Juyal @sakshijuyal_14
232 Followers 124 Following Research scholar @IITK || Alumnus @IITMadras || Total synthesis | C-H activation | Asymmetric Catalysis