Olefination of carbonyl compounds with gem-dizincioalkanes, bis(iodozincio)methane, 1,1-bis(iodozincio)ethane, and bis(bromozincio)methyltrimethylsilane, afforded the corresponding olefins in good to excellent yields.
Synthesis of γ,δ,-unsaturated α-amino acids from allylsilanes and glycidyl cation equivalents
作者:Hendrik H. Mooiweer、Henk Hiemstra、W.Nico Speckamp
DOI:10.1016/s0040-4020(01)89098-0
日期:——
The synthesis of a series of γ,δ-unsaturated N-protected α-amino acid methyl esters from the coupling of different allylsilanes and glycidyl cation equivalents 6 and 7 is described. Reactions with methoxyglycine derivative 6 are induced with BF3·OEt2; in the case of chloroglycine derivative 7 SnCl4 is used as Lewis acid. Reactions are fully regioselective, but show low stereoselectivity. The conversion
Silyl-substituted bis(bromozincio)methanes (RMe2SiCH(ZnBr)2; R = Me, Ph, and p-MeO-C6H4), prepared from the corresponding dibromides by Pb catalyzed reaction with zinc, reacted stepwise with two different electrophiles, R1X and E+, yielding R1-CH(SiMe2R)-E.