α-Alkylation versus retro-O-Michael/γ-alkylation of bicyclic N,O-acetals: an entry to α-methylthreonine
摘要:
The synthesis of a new threonine equivalent based on a bicyclic N,O-acetal substructure incorporating four stereogenic centres is developed from Boc-L-threonine methyl ester in one step. Its use as an excellent chiral building block was demonstrated in a new diastereoselective synthesis of alpha-methylthreonine by an alpha-alkylation reaction and in the synthesis of chiral alpha,beta-dehydroamino acid derivatives, using the tandem retro-O-Michael/gamma-alkylation reactions as key steps. (C) 2008 Elsevier Ltd. All rights reserved.
Asymmetric Synthesis of All Stereoisomers of α-Methylthreonine Using an Organocatalytic Steglich Rearrangement Reaction as a Key Step
作者:Harald Gröger、Friedrich Dietz
DOI:10.1055/s-0029-1217140
日期:——
An efficientsyntheticroute to all four stereoisomers of α-methylthreonine has been established. Each type of stereoisomer has been isolated in diastereomerically pure form and with an enantiomeric excess of at least 86% ee. The key step in this multi-step synthesis is an enantioselective organocatalytic Steglich rearrangement reaction of O-acetylated azlactones. The Steglich rearrangement was also
Moon, Sung-Hwan; Ohfune, Yasufumi, Journal of the American Chemical Society, 1994, vol. 116, # 16, p. 7405 - 7406
作者:Moon, Sung-Hwan、Ohfune, Yasufumi
DOI:——
日期:——
Novel Enantioselective Synthesis of α-Methylthreonines and α,β-Dimethylcysteines
作者:Hui Shao、Jaimie K. Rueter、Murray Goodman
DOI:10.1021/jo971983u
日期:1998.7.1
α-Methylserinals as an access to α-methyl-β-hydroxyamino acids: application in the synthesis of all stereoisomers of α-methylthreonine
作者:Alberto Avenoza、Jesús H. Busto、Francisco Corzana、Jesús M. Peregrina、David Sucunza、Marı́a M. Zurbano
DOI:10.1016/j.tetasy.2003.12.001
日期:2004.2
The asymmetric synthesis of all stereoisomers of alpha-methylthreonine using a stereodivergent synthetic route starting from (S)- and (R)-N-Boc-N,O-isopropylidene-alpha-methylserinals is reported. The key step involves the asymmetric addition of methylmagnesium bromide to these aldehydes with a high level of asymmetric induction being observed. This methodology represents a powerful tool for the synthesis of different beta-substituted alpha-methylserines. (C) 2003 Elsevier Ltd. All rights reserved.