Influence of the Catalytic Conditions on the Selectivity of the Pd‐Catalyzed Heck Arylation of Acrolein Derivatives.

Abstract

Influence of the Catalytic Conditions on the Selectivity of the Pd-Catalyzed Heck Arylation of Acrolein Derivatives. -The Heck arylation of a variety of aryl bromides with acrolein is readily achieved in the presence of the Hermann-Beller palladacycle. When the diethylacetal of acrolein is used, the choice of the catalyst affects the selectivity of the reaction dramatically. -(NOEL, S.; DJAKOVITCH*, L.; PINEL, C.; Tetrahedron Lett. 47 (2006) 23, 3839-3842; Inst. Rech. Catal., CNRS, Univ. Claude Bernard Lyon, F-69626 Villeurbanne, Fr.; Eng.) -Mais 37-048

Rhodium-Catalyzed Enal Transfer with N-Methoxypyridazinium Salts

“…The most direct approach to enals would be functionalization of substrates with readily accessible enals through enal-transfer reactions (Scheme ). The transition-metal-catalyzed cross coupling of acrolein by Mizoroki–Heck and C–H activation approaches allows direct enal transfer to aryl and heteroaryl substrates (Scheme a). , In a complementary approach, organocatalytic γ-functionalization of enals through dienamine activation provides enal transfer to C/N electrophiles (Scheme b) . However, the former approach is limited to aryl/heteroaryl derivatives, whereas the later suffers from competitive α-functionalization and cycloaddition pathways of the conformationally labile dienamine intermediate.…”