Understanding Site Selectivity in the Palladium-Catalyzed Cross-Coupling of AllenylsilanolatesWe are grateful to the National Science Foundation (NSF CHE-1151566) for generous financial support. A.A. thanks the University of Illinois and Eli Lilly and Co. for graduate fellowships
Received: 18 April 2017
Accepted after revision: 22 May 2017
12 July 2017 (eFirst)
Published as part of the Cluster Silicon in Synthesis and Catalysis
Allenylsilanolates can undergo cross-coupling at the α- or γ-terminus, and site selectivity appears to be determined by the intrinsic transmetalation mechanism. Fine-tuning of concentration, nucleophilicity, and steric bulk of the silanolate moiety allows for the selective formation of one isomer over the other. Whereas the α-isomer can be obtained in synthetically useful yield, the γ-isomer is favored only when employing reaction conditions that are inevitably associated with diminished reactivity.