摘要:
1-Iodoalkynes are formed in moderate to high yields from readily accessible benzylic and allylic alkyl bromides by a one-pot homologation/double elimination procedure with iodoform (CHI3). The developed conditions include facile purification and avoid the use of an excess of triphenylphosphine (PPh3), as described in classical Corey-Fuchs iodoalkynylation conditions. Replacing CHI3 with CHI2CI allows the isolation of the corresponding gem-(2)-chloro-(E)-iodoalkene in good yield and stereoselectivity. Moreover, the use of benzhydryl bromides as nucleophiles enables the synthesis of trisubstituted alkenes under similar reaction conditions.