Catalytic asymmetric cyclopropanation of heteroaryldiazoacetates

Rh-2(S-DOSP)(4)-catalyzed decomposition of heteroaryldiazoacetates in the p resence of styrene results in highly diastereoselective and enantioselectiv e cyclopropanations. Heteroaryldiazoacetates containing both electron-rich and electron-deficient heterocycles, such as thiophene, furan, pyridine, in dole, oxazole, isoxazole, and benzoxazole, are effective in this chemistry. These studies broaden the range of diazo compounds containing both electro n-withdrawing and electron-donating groups, which undergo highly diastereos elective cyclopropanations.