Palladium Precatalysts for Decarbonylative Dehydration of Fatty Acids to Linear Alpha Olefins

Transition-metal-catalyzed
decarbonylative dehydration of even-numbered
fatty acids to give valuable odd-numbered alpha olefins has so far
been performed using approaches in which the catalyst is formed in
situ. We show that well-defined Pd­(bis-phosphine) precatalysts eliminate
the need for excess phosphine and selectively produce linear alpha
olefins under mild conditions and with substantially increased turnover
frequency (TOF) and substrate scope. In particular, the new precatalyst
Pd­(cinnamyl)­Cl­(DPEPhos) (5) selectively converts substrates
containing unprotected aliphatic-alcohol and amine functional groups
to their corresponding linear alpha olefins.