Asymmetric synthesis of quaternary α-amino acids using d-ribonolactone acetonide as chiral auxiliary
摘要:
We describe a new simple methodology to prepare enantiopure alpha,alpha-dialkylglycines based on the use of commercially available D-ribonolactone as a chiral auxiliary. Enantiopure alpha-methyl and alpha-butyl series are prepared through diastereoselective alkylation and subsequent Schmidt rearrangement of alpha,alpha-dialkylacetoacetates of D-ribonolactone acetonide. Absolute configuration was assigned through preparation of enantiopure 4,4-disubstituted 3-methyl-2-pyrazolin-5-ones. (C) 1999 Elsevier Science Ltd. All rights reserved.
Asymmetric synthesis of quaternary α-amino acids using d-ribonolactone acetonide as chiral auxiliary
摘要:
We describe a new simple methodology to prepare enantiopure alpha,alpha-dialkylglycines based on the use of commercially available D-ribonolactone as a chiral auxiliary. Enantiopure alpha-methyl and alpha-butyl series are prepared through diastereoselective alkylation and subsequent Schmidt rearrangement of alpha,alpha-dialkylacetoacetates of D-ribonolactone acetonide. Absolute configuration was assigned through preparation of enantiopure 4,4-disubstituted 3-methyl-2-pyrazolin-5-ones. (C) 1999 Elsevier Science Ltd. All rights reserved.