Total chemical synthesis of 2-ethenyl-3,5-dimethylpyrazine and 3-ethenyl-2,5-dimethylpyrazine
作者:Toshinari H Kurniadi、Rachid Bel Rhlid、Marcel-A Juillerat、Thierry Gefflaut、Jean Bolte、Ralf G Berger
DOI:10.1016/s0040-4020(03)00948-7
日期:2003.8
2-ethenyl-3,5-dimethylpyrazine 1 and 3-ethenyl-2,5-dimethylpyrazine 2 were synthesized via a new chemical route. The key steps of the synthesis involve cyclocondenzation of 1-[bicyclo[2.2.1]5-hepten-2-yl]-1,2-propanedione and 1,2-propanediamine, aromatization of the resulting 5,6-dihydropyrazines, and subsequent Retro-Diels–Alder reaction to generate pyrazines 1 and 2. Pyrazine 1, a powerful odorant, was
Enantiogenic synthesis of (R)-(−)-3-hydroxy-1-penten-4-one
作者:Toshinari H. Kurniadi、Rachid Bel Rhlid、Marcel A. Juillerat、Martin Schüler、Ralf G. Berger
DOI:10.1016/s0957-4166(02)00800-5
日期:2003.2
Condensation of pyruvate and acrolein with whole cells of baker's yeast resulted in a mixture of 3-hydroxy-1-penten-4-one 1 and 4-hydroxy-1-penten-3-one 2. The absolute configuration (R) and the enantiomeric excess (ee 72%) of the compound 1 were determined. (C) 2003 Elsevier Science Ltd. All rights reserved.