The 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic Dicyanomethylides with Phenylsulfinylethene and Bis(trimethylsilyl)ethyne: Synthesis of 1,2-Unsubstituted 3-Cyanoindolizines
Pyridinium and diazinium dicyanomethylides underwent 1,3-dipolar cycloaddition-extrusion reactions with phenylsulfinylethene, producing the corresponding 3-cyanoindolizines in moderate to good yields. 1,3-Dipolar cycloadditions of these ylides with bis(trimethylsilyl)ethyne gave either the 1,2-bis(trimethylsilyl)-3-cyanoindolizines or the 1-trimethylsilyl-3-cyanoindolizines, or mixtures of these, depending
Cycloaddition reactions of cycloimmonium ylides with triphenylcyclopropene
作者:Kiyoshi Matsumoto、Takane Uchida
DOI:10.1039/p19810000073
日期:——
course of the reaction is discussed qualitatively. The pyrazinium dicyanomethylide (16) with TPP produces the 7-azaindolizine (19), whereas pyridazinium (17) and phthalazinium (18) dicyanomethylides give the primary adducts (20) and (21), respectively. Reaction of pyridinium bis(alkoxycarbonyl)methylides (22) with TPP gives, however, generally poor or no yield of the indolizines.
Cyclooctyne smoothly underwent 1,3-dipolar cycloaddition with pyridinium dicyanomethylides to afford the corresponding indolizines (8-cyario-7-azatricyclo[7.6.0.02,7]pentadeca-1,3,5,8-tetraenes) in excellent yields.