1,3-cycloadditions of aliphatic thione S-methylides to dimethyl 2,3-dicyanofumarate and 2,3-dicyanomaleate; a test case for steric course and mechanism
作者:Grzegorz Mloston、Elke Langhals、Rolf Huisgen
DOI:10.1016/s0040-4039(01)93790-6
日期:1989.1
The 1,3-cycloadditions of thioneS-methylides and to dimethyl 2,3-dicyanofumarate and 2,3-dicyanomaleate are nonstereospecific. A preceding cis,trans isomerization of the unsaturated dipolarophiles catalyzed by the thiadiazolines (precursors of the thioneS-methylides) had to be suppressed in order to clarify the stereochemical leakage during the cycloaddition.