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Vinylogous Mukaiyama–Michael Reactions between 2‐Silyloxyfurans and Cyclic Enones or Unsaturated Oxo Esters
Author(s) -
Chabaud Laurent,
Jousseaume Thierry,
Retailleau Pascal,
Guillou Catherine
Publication year - 2010
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201000504
Subject(s) - chemistry , stereocenter , michael reaction , lewis acids and bases , enone , stereochemistry , organic chemistry , medicinal chemistry , catalysis , enantioselective synthesis
Lewis acid catalyzed vinylogous Mukaiyama–Michael (VMM) reactions between 2‐(trialkylsilyloxy)furans 1 and α,β‐unsaturated cyclic enones 2 or oxo esters 4 have been investigated. Both substrates proved to be useful Michael acceptors in the title reaction, giving the butenolides 3 and 5 in good yields. A comparative study between the α,β‐unsaturated cyclic enones 2 and the oxo esters 4 as Michael acceptors showed better diasterecontrol with the latter class of compounds. In both series, crystal structures of the major isomers revealed anti relationships of newly formed stereogenic centers. From these data, two types of transition states could be proposed: an open TS with antiperiplanar orientation or a Diels–Alder‐like TS with exo approach.