An additive-free enantioselective hydrogenation of β,β-disubstituted unsaturated carboxylicacids catalyzed by the Rh–(R,R)-f-spiroPhos complex has been developed. Under mild conditions, a wide scope of β,β-disubstituted unsaturated carboxylicacids were hydrogenated to the corresponding chiral carboxylicacids with excellent enantioselectivities (up to 99.3% ee). This methodology was also successfully
Asymmetric synthesis of both enantiomers of esters and γ-lactones from optically active 1-chlorovinyl p-tolyl sulfoxides and lithium ester enolates with the formation of a tertiary or a quaternary carbon stereogenic center at the β-position
作者:Shimpei Sugiyama、Tsuyoshi Satoh
DOI:10.1016/j.tetasy.2004.11.085
日期:2005.2
synthesized from aldehydes or unsymmetricalketones and (R)-(−)-chloromethyl p-tolyl sulfoxide in two or three steps, with the lithium enolate of tert-butyl acetate gave optically active adducts in 99% chiral induction from the sulfur stereogenic center. The adducts were converted to optically active esters, carboxylic acids, and γ-lactones, which have a tertiary or a quaternarycarbon stereogenic center at