condensation or ring-closing alkene metathesis, were the key steps in these syntheses. The C/Si pairs 1a/1b, 2a/2b, and 3a/3b were studied for their olfactory properties. All compounds possess green-fruity galbanum-type odors with pineapple aspects and thus are olfactorily related. However, sila-analogues 1b–3b were found to be weaker than the corresponding parent carbon compounds 1a–3a. This effect is most pronounced
Versatile desilylative cross-coupling of silyl enol ethers and allylic silanes via oxovanadium-induced chemoselective one-electron oxidation
作者:Toshikazu Hirao、Takashi Fujii、Yoshiki Ohshiro
DOI:10.1016/s0040-4020(01)81753-1
日期:1994.8
The chemoselective cross-coupling of silylenolethers and allylic silanes to γ,δ-unsaturated ketones is achieved by the oxovanadium (V)-induced oxidative desilylation of the more readily oxidizable organosilicon compounds.
to produce unisolable allylchromium species which add efficiently to aldehydes or ketones with high degree of stereo- and chemoselectivity. Particularly, high threo selectivity is observed in the reaction of aldehydes and 1-bromo-2-butene and is ascribed to a chair-like six-membered transition state. Simple reduction of allylic and benzylic halides produces biallyls and bibenzyls, while gem-dibromocyclopropanes