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Diastereo‐ and Enantioselective Synthesis of Lignan Building Blocks by Tandem Michael Addition/Electrophilic Substitution of Lithiated α‐Amino Nitriles to Furan‐2(5 H )‐one
Author(s) -
Enders Dieter,
Kirchhoff Jochen,
Lausberg Vivien
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619960904
Subject(s) - enantioselective synthesis , chemistry , furan , stereocenter , michael reaction , lignan , alkylation , electrophile , enantiomer , stereochemistry , tandem , organic chemistry , catalysis , materials science , composite material
Starting from chiral α‐amino nitriles ( S,S,R/S )‐ 3 , we prepared β‐aroyl‐γ‐butyrolactones ( S )‐ 5 as well as 2,3‐disubstituted γ ‐butyrolactones ( S,S )‐ or ( R,S,R )‐ 6 in high yields and with high enantiomeric excesses by conjugate addition to butenolide, followed by protonation, α‐alkylation or α‐aldol addition, respectively. The introduction of one up to three stereogenic centers opens a flexible and highly efficient diastereo‐ and enantioselective route to 2,3‐dibenzylated γ‐butyrolactones 6 , which proved to be important lignan building blocks.