Diastereoselective syntheses of functionalized five-membered carbocycles and heterocycles by a SmI2-promoted intramolecular coupling of bromoalkynes and alpha,beta-unsaturated esters.

An intramolecular coupling of bromoalkynes with alpha,beta-unsaturated esters afforded functionalized five-membered carbocycles and heterocycles with high diastereoselectivities in excellent yields. The vinyl bromides newly generated as the products serve as adequate intermediates for further chemical modification.