Chiral glycine cation equivalents: N-acyliminium species derived from diketopiperazines
作者:Steven D. Bull、Stephen G. Davies、A. Christopher Garner、Michael D. O'Shea、Edward D. Savory、Emma J. Snow
DOI:10.1039/b207457p
日期:2002.11.13
Studies towards a N,N′-bis(p-methoxybenzyl)diketopiperazine asymmetric glycine cation equivalent for the synthesis of homochiral α-amino acids are described. The oxidation of enolate 3 with molecular oxygen provides either a mixture of hydroxylated diketopiperazines 7 and 8 or trione 10 depending upon the reaction conditions. The nucleophilic reduction of trione 10 and the reaction of acetoxy N-acyliminium ion precursors 5 and 6, derived from 7 and 8, with allyltrimethylsilane and boron trifluoride etherate is examined and a model for the stereoselectivity observed in these additions is presented.
本文介绍了一种 N,N′-双(对甲氧基苄基)二酮哌嗪不对称甘氨酸阳离子等价物用于合成同手性 α-氨基酸的研究。根据反应条件的不同,烯醇 3 与分子氧的氧化反应可生成羟基化二酮哌嗪 7 和 8 的混合物或三酮 10。研究了三酮 10 的亲核还原以及由 7 和 8 衍生出的乙酰氧基 N-酰亚胺离子前体 5 和 6 与烯丙基三甲基硅烷和三氟化硼醚的反应,并提出了在这些加成中观察到的立体选择性模型。