Enantioselective [3+2] Cycloaddition of Allenylsilanes with α-Imino Esters

Significance

The first enantioselective [3+2] cycloaddition reaction of 1-alkyl-substituted allenylsilanes with an α-imino ester is reported using a chiral Cu(I) catalyst. The presence of an α-alkyl group was essential for the reaction to succeed and a range of alkyl substituents was demonstrated. Use of a highly reactive aldimine is necessary to drive the reaction and only one example of an iminoester substrate gave the desired product. The vinyl silane functionality in the dehydroproline products allows further derivatization.