Diastereoselective Synthesis of Cephalotaxus Esters via Asymmetric Mukaiyama Aldol Reaction
作者:Guo-Zhen Ma、Peng-Fei Li、Lu Liu、Wei-Dong Z. Li、Li Chen
DOI:10.1021/acs.orglett.7b00743
日期:2017.5.5
carbon stereocenter of the side chain of cephalotaxus esters by means of highly diastereoselective Mukaiyama aldol reactions between α-keto esters (2) and a (Z)-α-chloro ketene silyl acetal. This protocol permitted synthesis of cephalotaxus esters including six natural products in good to excellent yields (up to 94%) with highdiastereoselectivities (dr up to 97:3) and could be performed on a multigram
Pyruvic Acid Dimethylhydrazone. A Synthetic Equivalent of the Pyruvic Acid Dianion
作者:Inés Tapia、Victoria Alcazar、Joaquín R. Moran、Cruz Caballero、Manuel Grande
DOI:10.1246/cl.1990.697
日期:1990.5
The pyruvic acid dimethyl hydrazone can be easily prepared in ether. This compound, after deprotonation with alkyllithium, forms a strong nucleophile which on treatment with electrophiles and acidic work up yield α-ketoacids, α-hydroxybutenolides or α,γ-diketoacids.