Cross‐Coupling of Triallyl(aryl)silanes with Aryl Bromides and Chlorides: An Alternative Convenient Biaryl Synthesis

Abstract

Abstract Cross‐coupling of a diverse range of aryl bromides with triallyl(aryl)silanes is effective in the presence of PdCl 2 /PCy 3 and tetrabutylammonium fluoride (TBAF) in DMSO‐H 2 O to give various biaryls in good yields. It is worthwhile to note that the all‐carbon‐substituted arylsilanes, stable towards moisture, acid, and base and easily accessible, serve as a highly practical alternative to their aryl(halo)silane counterparts. A catalyst system consisting of [(η 3 ‐C 3 H 5 )PdCl] 2 and 2‐[2,4,6‐( i ‐Pr) 3 C 6 H 2 ]‐C 6 H 4 PCy 2 and use of TBAF⋅3 H 2 O in THF‐H 2 O are effective especially for the cross‐coupling with aryl chlorides. Both of the catalyst systems tolerate a broad spectrum of common functional groups. The high efficiency of reactions is presumably due to the ready cleavage of the allyl groups upon treatment with TBAF⋅3 H 2 O and an appropriate amount of water. Diallyl(diphenyl)silane also cross‐couples with various aryl bromides and chlorides in good yields, whereas allyl(triphenyl)silane gives the cross‐coupled products in only moderate yields. Through sequential cross‐coupling of bromochlorobenzenes with different arylsilanes, a range of unsymmetrical terphenyls are accessible in good overall yields.