Unprecedented asymmetric induction through configurationally stable lithium N-(α-methylbenzyl)phosphinamides. A new entry to enantiomerically pure γ-aminophosphinic acids and esters
Unprecedented asymmetric induction through configurationally stable lithium N-(α-methylbenzyl)phosphinamides. A new entry to enantiomerically pure γ-aminophosphinic acids and esters
Asymmetric Deprotonation−Substitution of <i>N</i>-Pop-benzylamines Using [RLi/(−)-Sparteine]. Enantioselective Sequential Reactions and Synthesis of N-Heterocycles
Pop-directed asymmetric deprotonation of benzylic amines using [n-BuLi/(-)-sparteine] provides an efficient method for the synthesis of chiral NC alpha and NC alpha,alpha' derivatives with total selectivity with respect to competing allylic and ortho lithiation. The method described herein offers a straightforward route of accessing chiral N-Pop-protected nitrogen heterocycles.
Phosphinamide-Directed Benzylic Lithiation. Application to the Synthesis of Peptide Building Blocks
作者:Pascual Oña Burgos、Ignacio Fernández、María José Iglesias、Santiago García-Granda、Fernando López Ortiz
DOI:10.1021/ol7028096
日期:2008.2.1
N-Benzyldiphenylphosphinamides are deprotonated at the NC alpha position diastereospecifically upon treatment with t-BuLi in diethyl ether at low temperature. The reaction of the anions with alkyl, acyl, and tin halides, aliphatic and aromatic aldehydes, and Michael acceptors allowed installation of a variety of functional groups into the benzylic arm in excellent yields. Cleavage of the P-N linkage affords 1,2-amino alcohols and alpha-, beta-, and gamma-amino acids.