.alpha.-Oximino amide trianions in the stereoselective synthesis of isoxazolines and .gamma.-hydroxy .alpha.-amino acids
作者:Anthony G. M. Barrett、Dashyant Dhanak、Suzanne A. Lebold、Mark A. Russell
DOI:10.1021/jo00005a042
日期:1991.3
The trianions 17 and 33, which were prepared from the corresponding alpha-oximino amides 7 and 30, were reacted with 4-methoxybenzaldehyde to stereoselectively provide, on acidification, the corresponding trans-substituted isoxazoline-3-carboxamides 8 and 31/32, respectively. Additionally, the dianion 24, which was prepared from the corresponding O-silyl oxime 22, was reacted with 4-methoxybenzaldehyde to stereoselectively give the anti beta-hydroxy oxime 23. Reduction of 8 and 26 stereoselectively gave the 2,3-syn-3,4-anti amino amides 11 and 27. Amides 11 and 27 were subsequently converted to the gamma-hydroxy-alpha-amino acids 12 and 29 and the corresponding lactones 13 and 28. Amino acid 29 is the N-terminal amino acid of the antifungal agent nikkomycin B.