Nickel-catalyzed asymmetric grignard cross-coupling of dinaphthothiophene giving axially chiral 1,1'-binaphthyls.
Asymmetric cross-coupling of dinaphtho[2,1-b:1',2'-d]thiophene with ArMgBr (Ar = Ph, 4-MeC6H4, 4-MeOC6H4) proceeded with high enantioselectivity in THF at 20 degrees C in the presence of 3 mol % of a nickel catalyst generated from Ni(cod)2 and a chiral oxazoline-phosphine ligand to give high yields of axially chiral 2-mercapto-2'-aryl-1,1'-binaphthyls, whose enantiomeric excesses are over 93%. The mercapto group in the chiral binaphthyl was converted into iodo, boryl, and phosphino groups without racemization.
Shimada
Toyoshi
T
Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Japan.
Cho
Yong-Hwan
YH
Hayashi
Tamio
T