Palladium-CATALYZED TANDEM COUPLING REACTION OF ALKYNE, CONJUGATED DIENE, AND TRIETHYLBORANE

Copper-Catalyzed Stereodefined Construction of Acrylic Acid Derivatives from Terminal Alkynes via CO2 Insertion

“…Furthermore, similar multicomponent coupling reactions involving conjugated dienes with terminal alkynes in the presence of a Pd catalyst and Et 3 N as a base could be applicable for the tandem dimerization of conjugated dienes to form 1,4,9-decatrienes. 14 Based on the results of these multicomponent coupling reactions, we envisaged the use of CO 2 as an electrophilic reagent instead of π-allylpalladium in the presence of trialkylboranes and transition-metal catalysts. We could thus succeed in the three-component coupling reaction of an alkyne, a trialkylborane, and CO 2 to yield α-substituted acrylic acids as a single product.…”

“… In this case, the terminal alkyne reacted with the trialkylborane to give the alkynyltrialkylborate, which was followed by the 1,2-alkyl migration process; then the transmetalation of alkenylborane with π-allylpalladium species provided the stereodefined trisubstituted alkenes. Furthermore, similar multicomponent coupling reactions involving conjugated dienes with terminal alkynes in the presence of a Pd catalyst and Et 3 N as a base could be applicable for the tandem dimerization of conjugated dienes to form 1,4,9-decatrienes …”