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Highly 1,2‐ trans Stereoselective Allylations of 1,2‐ O ‐Isopropylidene‐Protected Glycofuranosides
Author(s) -
GarcíaTellado Fernando,
de Armas Pedro,
MarreroTellado José Juan
Publication year - 2000
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(20000804)39:15<2727::aid-anie2727>3.0.co;2-i
Subject(s) - stereoselectivity , chemistry , acetal , bicyclic molecule , anomer , stereochemistry , tetrahydrofuran , lewis acids and bases , protecting group , ring (chemistry) , organic chemistry , catalysis , alkyl , solvent
A remarkable bicyclic acetal template effect is responsible for the complete 1,2‐ trans stereoselectivity achieved in Lewis acid promoted allylations of 1,2‐ O ‐isopropylidene‐protected furanosides [Eq. (1)]. This stereoselectivity occurs regardless of the other substituents on the tetrahydrofuran ring. The bicyclic acetal acts as a basic, stable anomeric protecting group, and activates the carbohydrate anomeric position and directs the stereochemical outcome of the substitution reaction at this center.