Chelation-controlled highly diastereoselective catalytic hydrogenation of γ-hydroxy-α-methylenecarboxylic acid esters
作者:Hajime Nagano、Misaki Yokota、Yukiko Iwazaki
DOI:10.1016/j.tetlet.2004.02.111
日期:2004.4
We report the catalytichydrogenation of γ-hydroxy-α-methylenecarboxylic acidesters over Pd/C in the presence of 4 equiv of MgBr2 in tetrahydrofuran yielding predominantly the corresponding syn-γ-hydroxy-α-methylcarboxylic acidesters.
Enantioselective addition of β-functionalized allylboronates to aldehydes and aldimines. Stereocontrolled synthesis of α-methylene-γ-lactones and lactams
We report results regarding the development of condensations of chiral β-alkoxycarbonylallylboronates on aldehydes and imines. These allylboronates add in a highly enantioselective and diastereospecific manner to afford biologically and synthetically useful chiral α-methylene-γ-butyrolactones and lactams. The nature of the electrophile (aldehyde vs imine) is shown to have a dramatic influence on the