Desymmetrizing reductive aldol cyclizations of enethioate derivatives of 1,3-diones catalyzed by a chiral copper hydride.
Org Biomol Chem
; 10(30): 5971-8, 2012 Aug 14.
Article
em En
| MEDLINE
| ID: mdl-22576882
ABSTRACT
A range of enethioate derivatives of 1,3-diones underwent reductive aldol cyclizations catalyzed by a chiral copper hydride generated in situ from 5 mol% TaniaPhos (SL-T001-1), 5 mol% Cu(OAc)(2)·H(2)O, 5 mol% bipyridine and 2.0 equiv. of PhSiH(3), to furnish polycyclic ß-hydroxythioester products bearing three newly established contiguous stereocenters, with >982 dr and in up to 94% yield and 98% ee. The use of an amine such as bipyridine or 2,6-lutidine as additive results in an increase of the overall reaction rate. The major bicyclic aldol product has all substituents cis and can be rationalized by a reductively generated (Z)-enolate reacting with the dione via a cyclic transition state.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2012
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Article