Enantioselective Synthesis of Cyclopentenones via Rhodium-Catalyzed Kinetic Resolution and Desymmetrization of 4-Alkynals
作者:Ken Tanaka、Gregory C. Fu
DOI:10.1021/ja0266161
日期:2002.9.1
We have developed two new catalytic processes that provide efficient access to interesting chiral building blocks, cyclopentenones that bear tertiary and quaternary stereocenters, in high enantiomeric excess and very good yield. Structures such as these have potential utility in the synthesis of prostaglandins, pentenomycins, and related compounds.
We have developed catalytic isomerizations of 5-alkynals to γ-alkynyl ketones and cyclopent-1-enylketones using [RhP(OPh)3}2]BF4 as a catalyst. Cu(OTf)2 and AgBF4 are also effective catalysts for the formation of γ-alkynyl ketones. The substituents at the 4-positions in 5-alkynals play important roles in the selection of two different isomerization pathways. The first catalytic endo/trans hydroacylation
The transition-metal-catalyzed rearrangement of 5-alkynals to γ-alkynylketones and 1-cyclopentenylketones was developed using [Rh(P(OPh)3)2]BF4 or Cu(OTf)2 as a catalyst.