Highly regiocontrolled Pd-catalyzed cross-coupling reaction of terminal alkynes and allenylphosphine oxides.
The cross-coupling of a variety of terminal alkynes 1 with allenylphosphine oxides 2 catalyzed by a Pd(OAc)(2)-TDMPP system provided conjugated endo-enynes 3 solely, while the TCPC-catalyzed reaction of the same regents led to the exclusive formation of exo-isomers 4. The mechanistic rationale for these selective transformations was proposed. Synthetic usefulness of the prepared exo-enyne 4 was demonstrated in the synthesis of multisubstituted diarylbenzylphosphine oxides 5 via the Pd-catalyzed [4+2]-benzannulation reaction.
Rubin
Michael
M
Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA.
Markov
Jelena
J
Chuprakov
Stepan
S
Wink
Donald J
DJ
Gevorgyan
Vladimir
V