Remote stereocontrol in reactions between 4- and 5-alkoxyalk-2-enylstannanes and 1-alkoxycarbonylimines and analogues: stereoselective approaches to novel α-amino acids
作者:David J. Hallett、Nongluk Tanikkul、Eric J. Thomas
DOI:10.1039/c2ob25097g
日期:——
although a small amount of matching and mis-matching was observed. The allyltin trichloride 77 prepared from (4S)-4-(tert-butyldimethylsilyloxy)pent-2-enyl(tributyl)stannane 52 reacts with 1-alkoxycarbonylimines with the opposite 1,5-stereoselectivity to give the (4E)-2,6-syn-diastereoisomers 79. Matching and mismatching was more pronounced for tin(IV) chloride mediated reactions of (4R)-5-benzyloxy-4-me
由(4 S)-4-苄氧基戊-2-烯基(三丁基)锡烷1生成的三氯化烯丙基锡45与由乙醛酸酯制备的亚胺的反应进行的1,5-立体控制水平有利于(4 E)-2, 6-抗-2-(烷基氨基)-6-苄氧基庚-4-烯酸酯49。尽管观察到少量的匹配和错配,但受锡烷的手性控制的立体选择性在亚胺的任何固有立体化学偏见上均占优势。由(4S)-4-(叔丁基二甲基甲硅烷氧基)戊-2-烯基(三丁基)锡烷52制得的三氯化烯丙基锡77与具有相反的1,5-立体选择性的1-烷氧基羰基亚胺反应,得到(4 E)-2,6-顺-非对映异构体79。匹配和不匹配的原因更为明显氯化锡(IV)介导的(4 R)-5-苄氧基-4-甲基戊-2-烯基(三丁基)锡烷80与手性1-烷氧基羰基亚胺的反应,但有利于(4 E)-2,6- syn -2-烷基-的立体选择性和与非手性亚胺和类似物的反应中观察到芳基硫基-氨基-7-苄氧基-6-甲基庚-4-烯酸酯177