CC BY-ND-NC 4.0 · Synthesis 2019; 51(05): 1006-1020
DOI: 10.1055/s-0037-1611638
short review
Copyright with the author

Sulfur Betaines from S-Propargyl Xanthates. Unusual Chemistry from a Simple Functional Group

Laboratoire de Synthèse Organique associé au CNRS, Ecole Polytechnique, 91128 Palaiseau, France   eMail: samir.zard@polytechnique.edu
› Institutsangaben
Weitere Informationen

Publikationsverlauf

Received: 26. November 2018

Accepted: 28. November 2018

Publikationsdatum:
08. Januar 2019 (online)


Published as part of the 50 Years SYNTHESIS – Golden Anniversary Issue

This paper is dedicated with respect and affection to Professor Nguyen Trong Anh (Ecole Polytechnique).

Abstract

S-Propargyl xanthates undergo upon heating a [3,3] sigmatropic rearrangement followed by a reversible ring closure into a novel betaine. This betaine can be implicated in carbon–carbon bond forming processes, in the synthesis of esters, in the inversion of secondary alcohols, in the formation of alkenes, for the generation of rigid, cisoid dienes that are highly reactive in both inter- and intra-molecular Diels–Alder cycloadditions, and in various other synthetically useful transformations.

1 Introduction

2 An Unexpected Transformation

3 Evidence for the Betaine Intermediate

4 A Method for the Synthesis of Esters and for the Inversion of Secondary Alcohols

5 A General Alkylation Process

6 The Case of Carbon Acids

7 A Synthesis of Alkenes

8 Further Trapping Experiments. Concerted or Not Concerted?

9 Rigid Cisoid Dienes

10 Propargyl Radicals

11 Concluding Remarks