transformations using chlorosilane reagents. The p-tolyl-substituted DIOPO (p-tolyl-DIOPO) was most effective for the reductive aldol reaction of chalcone and aldehydes with trichlorosilane, whereas the 2,8-dimethylphenoxaphosphine-derived DIOPO (DMPP-DIOPO) afforded the best enantioselectivity for the phosphonylation of conjugated aldehydes and the chlorinative aldol reaction of an ynone and benzaldehyde.
Chiral N,N'-dioxide-Ytterbium(III) complexes promoted the asymmetric addition of diethyl phosphate to aldehydes, giving the corresponding products with good yields and enantioselectivities. The addition of pyridine favored both reactivity and enantioselectivity. A possible catalytic cycle was proposed to explain the mechanism of the asymmetric hydrophosphonylation of aldehydes. (C) 2010 Elsevier Ltd. All rights reserved.