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Asymmetric and ‘ anti ’‐Selective Aldolisations of Acetates and Propionates. Preliminary Communication
Author(s) -
Oppolzer Wolfgang,
MarcoContelles José
Publication year - 1986
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19860690725
Subject(s) - propionates , chemistry , alternation (linguistics) , enantioselective synthesis , stereochemistry , medicinal chemistry , organic chemistry , catalysis , philosophy , linguistics
Starting from acetates 1 and propionates 6 , TiCl 4 ‐mediated addition of their silyketene acetals 2 and 7 to aldehydes gave aldols 4 and 9 , respectively, with high π‐face and ‘ anti ’ differentiation ( Schemes , and Tables 1 and 2 ). Alternation of the ( E / Z )‐enolate geometry led to reversed α‐ and β‐inductions ( 7 → 9b , 8 → 10b ). Non‐destructive removal of the auxiliary yielded enantiomerically pure β ‐hydroxycarboxylic acids 13 .