Inverse regioselectivity in the silylstannylation of alkynes and allenes: copper-catalyzed three-component coupling with a silylborane and a tin alkoxide

Abstract

Silylstannylation of alkynes and allenes has been found to proceed by three-component coupling using a silylborane and a tin alkoxide in the presence of a Cu(I) catalyst. The regioselectivities are completely inverse to those of the conventional silylstannylation under palladium catalysis.

Ni‐Catalyzed Stannylation of Aryl Esters via C−O Bond Cleavage

“…We started our investigations by reacting 1a with 2a, ab ench-stable stannyl reagent that can be prepared quantitatively in one step and in bulk quantities. [11][12][13] After systematic experimentation (Scheme 2), [14] ac ombination of [Ni-(cod) 2 ], L1,a nd CsF in toluene at 90 8 8Cp rovided the best results,a ffording 3a in 91 %y ield (entry 1). In line with our expectations,t he nature of the ligand proved to be critical.…”

Ni‐Catalyzed Stannylation of Aryl Esters via C−O Bond Cleavage

“…[11][12][13] After systematic experimentation (Scheme 2), [14] ac ombination of [Ni-(cod) 2 ], L1,a nd CsF in toluene at 90 8 8Cp rovided the best results,a ffording 3a in 91 %y ield (entry 1). [11][12][13] After systematic experimentation (Scheme 2), [14] ac ombination of [Ni-(cod) 2 ], L1,a nd CsF in toluene at 90 8 8Cp rovided the best results,a ffording 3a in 91 %y ield (entry 1).…”

Copper Catalysis for Synthesizing Main-Group Organometallics Containing B, Sn or Si

“…The three‐component silylstannylation was found to readily occur to afford 40a and 40′a in 86% yield with regioselectivity inverse to that of the previous Pd‐catalyzed silylstannylation ( 40a : 40′a = 93:7), when the reaction of 1‐octyne, a silylborane (PhMe 2 Si–B(pin), 39 ) and tributyltin tert ‐butoxide ( 11c ) was carried out in acetonitrile at room temperature in the presence of CuCl–P t Bu 3 catalyst (Scheme ) . Linear and branched aliphatic terminal alkynes could undergo the regioselective silylstannylation, where the stannyl moieties were predominantly attached to the terminal carbon of the alkynes.…”