Tetrahedron Letters

Practical and divergent synthesis of 1-and 5-substituted 3, 9-diazaspiro [5.5] undecanes and undecan-2-ones

H Yang, XF Lin, F Padilla, DM Rotstein

Index: Yang, Hanbiao; Lin, Xiao-Fa; Padilla, Fernando; Rotstein, David M. Tetrahedron Letters, 2008 , vol. 49, # 44 p. 6371 - 6374

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Citation Number: 3

Abstract

A divergent synthesis of 1-and 5-substituted 3, 9-diazaspiro [5.5] undecanes and undecan-2- ones is described, in which the key step is an efficient Michael addition of a lithium enolate to a tetrasubstituted olefin acceptor. A variety of substituents (butyl, phenyl, and propoxyl) were introduced at C-1 (5) in this manner. In addition, an asymmetric synthesis of one member of this series was achieved using an Evans oxazolidinone chiral auxiliary reagent.