Silylamination of electrophilic alkynes

The addition of simple silylamines to dialkyl acetylenecarboxylates was investigated yielding both E and Z-silylenamines in contrast to an earlier report. Silylamination was also achieved with propiolates, expanding the scope of the silylamination reactions. The E-silylenamine was found to be the major isomer formed for all reactions yielding silylenamines. Hydrolysis of both E and Z-silylenamines cleanly yields the E-enamine.