Facile access to stereodefined dienoates and cyclopropylenoates containing a trifluoromethyl group

Ethyl (2E,4E)-3-trifluoromethyl-2,4-dienoates 1a–e and ethyl (E)-3-trans-alkylcyclopropyl-4,4,4-trifluoro-2-butenoates 2a–e were prepared from the trans-alkenylboronic acids 3a–e and the trans-cyclopropylboronic acids 4a–e with ethyl (Z)-3-iodo-4,4,4-trifluoro-2-butenoate (5) by the Suzuki cross-coupling reaction in high yields (88–95%). The configurations of both 3a–e or 4a–e and 5 were retained in the reaction.