Synthesis of Isothiazole via the Rhodium-Catalyzed Transannulation of 1,2,3-Thiadiazoles with Nitriles

A synthetic method
for obtaining a wide variety of isothiazoles
by the Rh-catalyzed transannulation of 1,2,3-thiadiazoles with alkyl,
aryl, and heteroaryl nitriles, which proceeds via an α-thiavinyl
Rh-carbenoid intermediate, was developed. The results suggest that
during its reaction with nitriles, the α-thiavinyl carbene acts
as an umpolung 1,3-dipole equivalent, in contrast to its behavior
during its reaction with alkynes. The developed method was successfully
employed to synthesize pentaoligomeric arylene compounds consisting
of three benzene and two isothiazole rings.

本研究开发了一种合成方法，可通过铑（Rh）催化的1,2,3-噻二唑与烷基、芳基及杂芳基腈的转环化反应，制备多种异噻唑（isothiazoles）类化合物，该反应经由α-硫乙烯基铑卡宾中间体进行。研究结果表明，与炔烃反应时的行为不同，该α-硫乙烯基卡宾在与腈类反应时可作为极性反转的1,3-偶极体等价物。所开发的方法已成功用于合成由3个苯环与2个异噻唑环构成的五聚亚芳基化合物。