Synthesis of monosaccharide analogues in an enantio‐ and diastereoselective manner has been investigated. Asymmetric benzoyloxylation and subsequent aldol reaction using two amine catalysts effectively give monosaccharide analogues with controlled three stereogenic centers.
A novel chiral synthetic equivalent of glyoxal and its application to the asymmetric synthesis of O-protected α-hydroxy aldehydes
作者:Lino Colombo、Marcello Di Giacomo
DOI:10.1016/s0040-4039(99)00095-7
日期:1999.3
prepared in 83% yield from stannyloxazolidine 4. Grignard additions to the formyl group of compound 7 in the presence of Lewis acids afforded diastereomerically pure secondary carbinols 8. Protection of the hydroxyl group and unmasking of the oxazolidine ring gave O-protected α-hydroxy aldehydes 11, which were immediately reduced to the corresponding 1,2-diols 12.
practical one-pot three-step sequence is reported for the asymmetric synthesis of α-benzoyloxylated alcoholsfromprimaryalcohols. Good overall yields (36–52%) and enantioselectivities (91–94% e.e.) are obtained using a commercial organocatalyst in the key oxylation reaction. A simple modification in the protocol allows the formation of enantioenriched γ-benzoyloxylated α,β-unsaturated ester from alcohol
Chiral acetals: Stereocontrolled syntheses of 16-, 17-, and 18-hydroxyeicosatetraenoic acids, cytochrome P-450 arachidonate metabolites
作者:Bertrand Heckmann、Charles Mioskowski、Sun Lumin、J.R. Falck、Shouzuo Wei、Jorge H. Capdevila
DOI:10.1016/0040-4039(96)00059-7
日期:1996.2
Chiral adducts from Grignard or allylsilane additions to 1,3-dioxan/1,3-dioxolan-4-ones were exploited for the total synthesis of the R− and S-isomers of the title eicosanoids.