Process Research on [(2<i>S</i>)-(3-Fluorophenyl)-(1<i>S</i>)-(5-oxotetrahydrofuran- 2-yl)ethyl]carbamic Acid <i>tert</i>-Butyl Ester, a Lactone Intermediate for an Aspartyl Protease Inhibitor
作者:Frank J. Urban、V. John Jasys
DOI:10.1021/op030207n
日期:2004.3.1
yields for this conversion, the N−H of the BOC group in Weinreb amino acid amide 10 was deprotonated first with a simple Grignard reagent (methyl or benzylmagnesium halide) followed by Barbier reaction with magnesium metal and 2-(2-bromoethyl)-1,3-dioxane. The acetal group in 11 was opened oxidatively with ozone, and the resulting ester 15 was reduced selectively at low temperature with N-Selectride. Alternatively
从 S-BOC-(3-氟苯基)丙氨酸 3 开始制备内酯 [2S-(3-氟苯基)-1S-(5-氧代四氢呋喃-2-基)乙基]氨基甲酸叔丁酯 1 的两种方法是描述。(S)-(3-氟苯基)丙氨酸 N-甲基-N-甲氧基酰胺 10,即 3 的 Weinreb 酰胺,与 2-(2-1,3-二恶烷基)乙基溴化镁反应得到关键中间体酮缩醛 11。为了实现这种转化的高产率,Weinreb 氨基酸酰胺 10 中 BOC 基团的 N-H 首先用简单的格氏试剂(甲基或苄基卤化镁)去质子化,然后与金属镁和 2-(2-溴乙基)进行巴比尔反应-1,3-二恶烷。11中的缩醛基团被臭氧氧化开环,生成的酯15在低温下被N-Selectride选择性还原。或者,用三异丙醇铝在 2-丙醇中非对映选择性还原 11 中的酮部分,得到不需要的 (R,S)-非对映醇。酒精转化为甲磺酸盐,这是他...