Palladium-Catalyzed Decarboxylative Coupling of Allylic Alkynoates with Arynes

Abstract

A novel and selective protocol for the synthesis of 1-allyl-2-ethynylbenzenes has been developed by palladium-catalyzed decarboxylative coupling of allylic alkynoates with arynes. This new route allows for both sp-sp(2) and sp(2)-sp(3) couplings of allylic alkynoates with arynes in one pot involving a decarboxylation process.

Transition Metal-Catalyzed Decarboxylative Allylation and Benzylation Reactions

“…109 After some screening, very similar conditions to those reported by Rayabarapu and Tunge 108a were found to be useful in effecting the transformation. The reaction was quite general and tolerated rather large allenyl substituents (entry 1).…”

“…Tunge and Rayabarapu recognized that development of a useful decarboxylative coupling of allyl propiolates would obviate the need for the preparation and use of toxic tin reagents, effectively replacing transmetallation with decarboxylative metalation. 108a Thus, they initiated their study with the phenyl cinnamyl propiolate and found that a catalytic amount of Pd(PPh 3 ) 4 would facilitate the decarboxylative allylation in good yield in 2 h (Chart 23). These conditions proved to be quite general (Chart 23).…”

“…108a Byproduct 130 , observed when R′=Me, suggested that intermediates A could be intercepted by alkynes. Li and Liang recognized that use of more reactive alkynes, specifically benzynes derived from ortho -silyl triflates, would lead to a more general interceptive DcA to give products 131 .…”

“…Li and Liang recognized that use of more reactive alkynes, specifically benzynes derived from ortho -silyl triflates, would lead to a more general interceptive DcA to give products 131 . 108b …”

Copper‐Catalyzed Decarboxylative Cross‐Coupling of Potassium Polyfluorobenzoates with Aryl Iodides and Bromides

“…We reported a palladium-catalyzed decarboxylative coupling of oxalate monoesters with aryl halides, [10] and related decarboxylative reactions were also reported recently by the groups of Tunge, Li, Chruma, and others. [11] Herein we describe the first, copper-only systems that catalyze the decarboxylative coupling of potassium polyfluorobenzoates with aryl iodides and bromides [Eq. (1)].…”