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Asymmetric Allylation of α‐Ketoester‐Derived N ‐Benzoylhydrazones Promoted by Chiral Sulfoxides/ N ‐Oxides Lewis Bases: Highly Enantioselective Synthesis of Quaternary α‐Substituted α‐Allyl‐α‐Amino Acids
Author(s) -
ReyesRangel Gloria,
Bandala Yamir,
GarcíaFlores Fred,
Juaristi Eusebio
Publication year - 2013
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.22159
Subject(s) - chemistry , enantioselective synthesis , chirality (physics) , circular dichroism , enantiomer , lewis acids and bases , stereochemistry , enantiomeric excess , absolute configuration , medicinal chemistry , catalysis , organic chemistry , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
Chiral sulfoxides/ N ‐oxides ( R )‐ 1 and ( R , R )‐ 2 are effective chiral promoters in the enantioselective allylation of α‐keto ester N ‐benzoylhydrazone derivatives 3a , 3b , 3c , 3d , 3e , 3f , 3g to generate the corresponding N ‐benzoylhydrazine derivatives 4a , 4b , 4c , 4d , 4e , 4f , 4g , with enantiomeric excesses as high as 98%. Representative hydrazine derivatives 4a , 4b were subsequently treated with SmI 2 , and the resulting amino esters 5a , 5b with LiOH to obtain quaternary α‐substituted α‐allyl α‐amino acids 6a , 6b , whose absolute configuration was assigned as ( S ), with fundament on chemical correlation and electronic circular dichroism (ECD) data. Chirality 25:529–540, 2013 . © 2013 Wiley Periodicals, Inc.