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Synthesis of Functionalized 2‐Alkylidenetetrahydrofurans by Cyclization of 1,3‐Bis(trimethylsilyloxy)‐1,3‐butadienes with Epoxides
Author(s) -
Langer Peter,
Armbrust Holger,
Eckardt Tobias,
Magull Jörg
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20020315)8:6<1443::aid-chem1443>3.0.co;2-0
Subject(s) - chemoselectivity , chemistry , lewis acids and bases , epoxide , base (topology) , reaction mechanism , medicinal chemistry , organic chemistry , catalysis , mathematical analysis , mathematics
The Lewis acid mediated cyclization of epoxides with 1,3‐bis(trimethylsilyloxy)‐1,3‐butadienes, electroneutral equivalents of 1,3‐dicarbonyl dianions, results in the formation of 2‐alkylidenetetrahydrofurans with a great variety of substitution patterns and functional groups. This includes the synthesis of 2,3′‐bifuranylidenes and 7‐oxabicyclo[4.3.0]nonanes. The cyclization of dienes with functionalized epoxides containing base‐labile groups proceeds with good chemoselectivity. In all reactions, good regio‐ and E diastereoselectivities are observed. Based on the stereoselectivities observed for reactions of 1,2‐disubstituted epoxides, a working hypothesis for the mechanism of the reaction is suggested.