Synthetic Application of Cyanoaminosilanes as Azomethine Ylide Equivalents

Article abstract of DOI:10.1021/jo00221a010

A series of α-cyanoaminosilanes have been found to act as azomethine ylide equivalents.Treatment of these compounds with silver fluoride in the presence of electron-dificient alkynes and olefins gives substituted pyrroles and pyrrolidines in high yield.It was found that N-benzyl-N-(cyanomethyl)-N-<(trimethylsilyl)methyl>amine undergoes stereospecific cycloaddition with dimethyl fumarate and maleate.The stereospecificity of the reaction is consistent with a concerted cycloaddition reaction.The cycloaddition behavior of an unsymmetrically substituted α-cyanosilylamine with methyl propiolate was also examined and found to react with high overall regioselectivity.The synthetic utility of cyanoaminosilanes as azomethine ylide equivalents was demonstrated by the preparation of a Reniera isoindole alkaloid.The key step in the synthesis involved the reaction of 2-methyl-3-methoxyquinone with N-methyl-N-(cyanomethyl)-N-<(trimethylsilyl)methyl>amine in the presence of silver fluoride to give 2,5-dimethyl-6-methoxy-2H-isoindole-4,7-dione in good yield.