Stannyl cyclopropanes by diastereoselective cyclopropanations with (tributylstannyl)-diazoacetate esters catalyzed by Cu(I) N-heterocyclic carbene

by Gawley, R. E.; Narayan, S.

Catalyzed cyclopropanations of alkenes with Bu3SnC(=N-2)-CO2R (R = 5 Et, t-Bu) have been achieved in good yield with excellent diastereoselectivity to make stannyl cyclopropanes having two or three stereocenters, one of which is quaternary.