Premium
Mechanism and Origin of Stereoselectivity in Lewis Acid Catalyzed [2+2] Cycloadditions of Ketenes with Aldehydes
Author(s) -
Singleton Daniel A.,
Wang Yingcai,
Yang Hong Woon,
Romo Daniel
Publication year - 2002
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 - 10.1002/1521-3773(20020503)41:9<1572::aid-anie1572>3.0.co;2-b
Subject(s) - diastereomer , stereoselectivity , chemistry , limiting , lewis acids and bases , mechanism (biology) , catalysis , reaction mechanism , stereochemistry , organic chemistry , philosophy , epistemology , mechanical engineering , engineering
Divergent rate‐limiting steps for the formation of diastereomeric products! Evidence for this unexpected finding comes from experimental and theoretical studies of the title reaction. The predicted differing rate‐determining steps (rds) in the formation of cis‐ and trans ‐ β ‐lactones (see scheme; cy=cyclohexyl, TBS= tert ‐butyldimethylsilyl) are used to explain the stereoselectivity of these reactions and suggest that a broader range of mechanistic possibilities should sometimes be considered in reactions leading to diastereomeric products.