Synthesis of Dihydroxyethylene Isosteres of Dipeptides; 2. Isosteres of Leu-Ala and Leu-Val from Suitably Substituted 3-Dimethylphenylsilyl-4-octanolides
作者:Frank Rehders、Dieter Hoppe
DOI:10.1055/s-1992-26248
日期:——
Homochiral 2-alkyl-5-amino-3-hydroxy-5-octanolides 4a,b, 5b, 6b and 9a, representing protected Ï [CHOHCHOH] dipeptides, were prepared by stereospecific oxydesilylation of the appropriate 3-dimethylphenylsilyl derivatives, 1a-c and 7a. Alternatively, anti-selective Peterson elimination of the diastereomeric 3,4-trans-substituted γ-lactones 1a or 1b followed by esterification yielded methyl (2R,3E,5S)-5-(tert-butoxycarbonylamino)-2, 7-dimethyl-3-octenoate (14a), which on syn-bishydroxylation led to the 2R,3S,4S,5S- and 2R,3R,4R,5S-stereoisomers of Ï [CHOHCHOH]-L-leu-L-ala, 17a and 18a. In combination with the results of the preceding paper, a general procedure is outlined for the rapid synthesis of various diasteromers of dipeptide dihydroxyethylene isosteres.
通过立体选择性氧化硅化适当的3-二甲基苯基硅烷衍生物1a-c和7a,制备了手性2-烷基-5-氨基-3-羟基-5-辛内酯4a,b, 5b, 6b和9a,它们代表保护的Ï [CHOHCHOH]二肽。或者,对非对映异构体3,4-反式取代的γ-内酯1a或1b进行反选择性彼得森消除,然后进行酯化,得到甲基(2R,3E,5S)-5-(叔丁氧羰基氨基)-2,7-二甲基-3-辛烯酸酯(14a),对其进行同位双羟基化,得到Ï [CHOHCHOH]-L-亮氨酰-L-丙氨酰的2R,3S,4S,5S-和2R,3R,4R,5S-立体异构体17a和18a。结合前一篇论文的结果,概述了快速合成二肽二羟基乙烯异构体的各种非对映异构体的通用方法。