In the reaction with tert-butyloxycarbonyl anhydride (Boc2O), N-(o-vinylacetyloxy)benzenesulfonyl allylic amines 4a-c undergo concomitant O to N acyl migration to give N-(o-vinylacetyloxy)-N-(o-tert-butoxycarbonyloxy)benzenesulfonyl allylic amines 16a-c. In the presence of Grubbs’ second-generation catalyst, 16a-c are converted into N-arylsulfonyl-3,6-dihydropyridones 17a-c. The Boc group was removed from 17b and the resulting 18 was reductively cleaved with LiAlH4 to the ring-opened N-arylsulfonylamino alcohol 20 and with DIBAL to the ring-opened N-arylsulfonylamino aldehyde 21 that are close N-protected precursors of the Z-ethylenic pseudopeptidic analogue of l-Phe-Gly.
在与叔丁氧基羰基酸酐 (Boc2O) 的反应中,N-(邻
乙烯基乙酰氧基)苯磺酰基
烯丙胺 4a-c 伴随 O 至 N 酰基迁移,得到 N-(邻
乙烯基乙酰氧基)-N-(邻叔丁氧基羰氧基) )苯磺酰
烯丙胺16a-c。在格鲁布斯第二代催化剂存在下,16a-c 转化为 N-芳基磺酰基-3,6-
二氢吡啶酮 17a-c。从17b中除去Boc基团,并将所得的18用LiAlH 4 还原裂解成开环的N-芳基磺酰
氨基醇20,并用D
IBAL还原裂解成开环的N-芳基磺酰
氨基醛21,它们是Z-的紧密N-保护的前体L-Phe-Gly 的
乙烯假肽类似物。