A Cross-Metathesis Route to Functionalized α-Methyl α-Substituted Amino Acids
作者:Roy P. M. Storcken、Lavinia Panella、Floris L. van Delft、Bernard Kaptein、Quirinus B. Broxterman、Hans E. Schoemaker、Floris P. J. T. Rutjes
DOI:10.1002/adsc.200600446
日期:2007.1.8
A chemoenzymatic approach to the synthesis of functionalized α-methyl α-substituted amino acids is detailed. This involves amidase-mediated enzymatic resolution of α-methyl α-substituted side-chain ω-unsaturated amino acids followed by functionalization via cross-metathesis.
A practical asymmetric synthesis of α-methyl α-amino acids using a chiral Cu–salen complex as a phase transfer catalyst
作者:Yuri N Belokon'、R.Gareth Davies、Michael North
DOI:10.1016/s0040-4039(00)01247-8
日期:2000.9
The asymmetric C-alkylation of N-benzylidene alanine methyl ester has been achieved using a copper(II) (salen) complex as an asymmetric phase transfer catalyst and provides a practicalsynthesis of α-methyl α-aminoacids with up to 86% enantiomeric excess.
Ruthenium-catalyzed ring closing olefin metathesis of non-natural α-amino acids
作者:Floris P.J.T. Rutjes、Hans E. Schoemaker
DOI:10.1016/s0040-4039(96)02390-8
日期:1997.1
The use of various enantiopure amino acid-derived diolefins as substrates for the ring closing olefinmetathesis reaction (RCM) has been investigated. This reaction has been shown to be an efficient transformation for providing highly functionalized 6- and 7-membered ring amino acids.
Quaternized α,α′-Amino Acids via Curtius Rearrangement of Substituted Malonate–Imidazolidinones
作者:Maheswara Rao Gokada、Roger Hunter、Ana Andrijevic、Wade F. Petersen、Sauvik Samanta、Gerhard Venter、Sophie Rees-Jones
DOI:10.1021/acs.joc.7b01684
日期:2017.10.6
An efficient synthesis protocol is presented for accessing quaternized α-amino acids in chiral, nonracemic form viadiastereoselective malonate alkylation followed by C- to N-transposition. The key stereodifferentiating step involves a diastereoselective alkylation of an α-monosubstituted malonate–imidazolidinone, which is followed first by a chemoselective malonate PMB ester removal and then a Curtius
Cooperative Catalyst‐Enabled Regio‐ and Stereodivergent Synthesis of α‐Quaternary α‐Amino Acids via Asymmetric Allylic Alkylation of Aldimine Esters with Racemic Allylic Alcohols
作者:Lu Xiao、Xin Chang、Hui Xu、Qi Xiong、Yanfeng Dang、Chun‐Jiang Wang
DOI:10.1002/anie.202212948
日期:2022.11.14
The regio- and stereodivergent asymmetric α-allylation of aldimine esters with racemic allylic alcohols was enabled by cooperative catalysis. The Et3B additive plays a significant role in ionizing allylic alcohols to form electrophilic metal-π-allyl species and simultaneously promotes the formation of nucleophilic Cu-ylides. Computational mechanistic studies revealed the role of the Et3B additive and
醛亚胺酯与外消旋烯丙醇的区域和立体发散不对称 α-烯丙基化反应是通过协同催化实现的。Et 3 B 添加剂在电离烯丙醇以形成亲电子金属-π-烯丙基物质方面发挥重要作用,同时促进亲核铜叶立德的形成。计算机理研究揭示了 Et 3 B 添加剂的作用以及立体选择性和区域选择性的起源。