Stereoselective Synthesis of Unnatural Spiroisoxazolinoproline-Based Amino Acids and Derivatives
摘要:
A route to spiroisoxazolinoproline-based amino acid derivatives is reported in which exo-methyleneprolinate 4 (tert-butyl ester) reacts as a dipolarophile with nitrile oxides to generate spiroisoxazolinoprolinates 7/10/11 in good yields (70-75%) and with ca. 1:4 cis:trans diastereo-selectivity. tert-Butyl spiroisoxazolinoprolinates were separable by column chromatography and amenable to scale-up leading to single diastereoisomers of N-Boc and N-Fmoc protected spiroisox-azolinoproline amino acids.
Stereoselective Synthesis of Unnatural Spiroisoxazolinoproline-Based Amino Acids and Derivatives
摘要:
A route to spiroisoxazolinoproline-based amino acid derivatives is reported in which exo-methyleneprolinate 4 (tert-butyl ester) reacts as a dipolarophile with nitrile oxides to generate spiroisoxazolinoprolinates 7/10/11 in good yields (70-75%) and with ca. 1:4 cis:trans diastereo-selectivity. tert-Butyl spiroisoxazolinoprolinates were separable by column chromatography and amenable to scale-up leading to single diastereoisomers of N-Boc and N-Fmoc protected spiroisox-azolinoproline amino acids.
Stereoselective Synthesis of Unnatural Spiroisoxazolinoproline-Based Amino Acids and Derivatives
作者:Wei-Chieh Cheng、Yannan Liu、Melissa Wong、Marilyn M. Olmstead、Kit S. Lam、Mark J. Kurth
DOI:10.1021/jo025611j
日期:2002.8.1
A route to spiroisoxazolinoproline-based amino acid derivatives is reported in which exo-methyleneprolinate 4 (tert-butyl ester) reacts as a dipolarophile with nitrile oxides to generate spiroisoxazolinoprolinates 7/10/11 in good yields (70-75%) and with ca. 1:4 cis:trans diastereo-selectivity. tert-Butyl spiroisoxazolinoprolinates were separable by column chromatography and amenable to scale-up leading to single diastereoisomers of N-Boc and N-Fmoc protected spiroisox-azolinoproline amino acids.