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Asymmetric Cobalt‐Catalyzed Regioselective Hydrosilylation/Cyclization of 1,6‐Enynes
Author(s) -
You Yang'en,
Ge Shaozhong
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202100775
Subject(s) - hydrosilylation , stereocenter , cobalt , chemistry , enantioselective synthesis , stereospecificity , catalysis , regioselectivity , yield (engineering) , medicinal chemistry , organic chemistry , materials science , metallurgy
Abstract We report an enantioselective cobalt‐catalyzed hydrosilylation/cyclization reaction of 1,6‐enynes with secondary and tertiary hydrosilanes employing a catalyst generated in situ from the combination of Co(acac) 2 and ( R , S p )‐Josiphos. A wide range of oxygen‐, nitrogen‐, and carbon‐tethered 1,6‐enynes reacted with Ph 2 SiH 2 , (EtO) 3 SiH, or (RO) 2 MeSiH to afford the corresponding chiral organosilane products in high yields and up to >99 % ee . This cobalt‐catalyzed hydrosilylation/cyclization also occurred with prochiral secondary hydrosilane PhMeSiH 2 to yield chiral alkylsilanes containing both carbon‐ and silicon‐stereogenic centers with excellent enantioselectivity, albeit with modest diastereoselectivity. The chiral organosilane products from this cobalt‐catalyzed asymmetric hydrosilylation/cyclization could be converted to a variety of chiral five‐membered heterocyclic compounds by stereospecific conversion of their C−Si and Si−H bonds without loss of enantiopurity.