Sc(OTf)3-catalyzed intramolecular diastereoselective cyclization from tert-butoxycarbonyl to acyliminium ion
作者:Zhuo-Ya Mao、Chen Wang、Xiao-Di Nie、Xiao-Li Han、Han-Qing Dong、Chang-Mei Si、Bang-Guo Wei
DOI:10.1016/j.tet.2021.131959
日期:2021.3
An effective approach to access dyadic 1,3-oxazinan-2-ones 8a-8c and 4,4a,5,6-tetrahydro-[1,3]oxazino[3,4-a]quinolin-1(3H)-ones 8d-8h was developed through Sc(OTf)3-catalyzed intramolecular cyclization from tert-butoxycarbonyl to acyliminium ion 7a-7j. A variety of substituted N,O-acetals, with different ring size, proved to be suitable substrates for this transformation, and a series of (4aS,6S,7
一种访问二元1,3-恶嗪南-2-酮8a - 8c和4,4a,5,6-四氢-[1,3]恶嗪基[3,4-a]喹啉-1(3H)-酮的有效方法8d-8h是通过Sc(OTf)3催化的分子内环化反应从叔丁氧羰基到酰基亚胺离子7a-7j的反应而开发的。各种具有不同环尺寸的取代的N,O-缩醛被证明是该转化的合适底物,并且一系列(4 aS, 6 S, 7 R)-6-OTBS-7-取代的六氢吡咯[1 ,2-c] [1,3] oxazin-1-ones 11a-11j和其他手性二元1,3-oxazinan-2-ones 8i,8j,11k以中等收率合成,具有非对映选择性(dr > 99:1)。此外,通过这种有趣的路易斯酸催化的分子内环化过程获得了2,5-反式产物11a-11j。