Tetrahedron

Lithium n-benzyltrimethylsilylamide (LSA): a new reagent for conjugate addition-enolate trapping reactions

N Asao, T Uyehara, Y Yamamoto

Index: Asao, Naoki; Uyehara, Tadao; Yamamoto, Yoshinori Tetrahedron, 1988 , vol. 44, # 13 p. 4173 - 4180

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Citation Number: 46

Abstract

Lithium N-benzyltrimethylsilyl amide (LSA) adds to crotonates in a 1, 4-manner, though the reaction of ordinary lithium amides with α, β-unsaturated carbonyl compounds is accompanied with a 1, 2-addition and hydrogen abstraction at the γ-position. The conjugate addition via LSA followed by enolate trapping with electrophiles produces the corresponding α-substituted β-amino esters, which are, in turn, converted into β-lactams and α- ...