Concomitant Epoxide Deoxygenation and Deacetylation of Glycidyl Acetates Induced by Telluride Ion
摘要:
Treatment of glycidyl acetates with telluride ion (Te2-) produced by reduction of elemental Te with LiEt(3)BH yields allylic alcohols by loss of the epoxide oxygen atom and the acetyl group from the ester. If the glycidyl acetate is disubstituted at C-3, a rearrangement to an isomeric allylic alcohol competes with the deoxygenation-deacetylation. Triethylborane, a byproduct in the reduction of Te, is believed to play an important role as a Lewis acid since when it is absent or removed by addition of fluoride ion the reaction is extremely slow.
Enantioselective addition of (Z)- and (E)-alkenylzinc bromides to aldehydes: asymmetric synthesis of sec-allylalcohols
作者:Wolfgang Oppolzer、Rumen N. Radinov
DOI:10.1016/s0040-4039(00)93553-6
日期:1991.10
In situ prepared (Z)- and (E)-1-alkenylzinc bromides 5 were added to various aldehydes 1 in the presence of lithiated (+)-N-methylephedrine or (+)-2-(N,N-dimethylamino)-1,2-diphenylethanol to give sec. allyalcohols 7 in high optical purity with simple recovery of the chiral aminol 6.