使用二碘化钐促进β-酮异硫氰酸酯的分子内还原环化反应。

Intramolecular, reductive cyclization of beta-ketoisothiocyanates promoted by using samarium diiodide.

作者信息

Cho Min Seok, Lee In Sang, Kang Sung Ho, Kim Yong Hae

机构信息

Department of Chemistry, Center for Molecular Design and Synthesis, Korea Advanced Institute of Science and Technology, Daejon, 305-701, Korea.

出版信息

Chemistry. 2005 Feb 18;11(5):1452-8. doi: 10.1002/chem.200400676.

DOI:10.1002/chem.200400676

PMID:15651025

Abstract

A novel samarium diiodide (SmI2) promoted intramolecular cyclization of beta-ketoisothiocyanate, derived from alpha,beta-unsaturated esters and ammonium thiocyanate led to alpha-hydroxythiolactams and/or thiolactams in high yields. Treatment of beta-ketoisothiocyanate with two equivalents of SmI2 gave a mixture of alpha-hydroxythiolactam and thiolactam. Four equivalents of SmI2 afforded only thiolactam in high yields. The intramolecular cyclization took place with high to complete stereoselectivity. A mechanism to explain this transformation is proposed.

摘要

一种新型的二碘化钐（SmI₂）促进的β-酮异硫氰酸酯的分子内环化反应，该β-酮异硫氰酸酯由α,β-不饱和酯和硫氰酸铵衍生而来，能以高产率生成α-羟基硫内酰胺和/或硫内酰胺。用两当量的SmI₂处理β-酮异硫氰酸酯，得到α-羟基硫内酰胺和硫内酰胺的混合物。四当量的SmI₂仅以高产率提供硫内酰胺。分子内环化反应具有高至完全的立体选择性。本文提出了一种解释这种转化的机理。