Tandem Michael Addition/Amino-Nitrile Cyclization from 2-Formyl-1,4-DHP in the Synthesis of Novel Dihydroindolizine-Based Compounds
作者:Štefan Marchalín、Barbora Baumlová、Peter Baran、Hassan Oulyadi、Adam Daïch
DOI:10.1021/jo0615044
日期:2006.11.1
reagent 14 were investigated using four kinds of activated methylenes as nucleophiles. The key step of the sequential reaction was based on the highly diastereoselective tandem Michael addition/intramolecular amino-nitrile cyclization catalyzed by an organic base, which resulted in the formation of 1,7-dihydroindolizines in a diastereoselective manner. The process seems to be a straightforward one and
描述了一种简单有效的方法,用于从外消旋的2-甲酰基-1,4-DHP试剂5开始合成具有不同饱和度的小取代吲哚并嗪文库。该试剂及其Knoevenagel相应的2-dicyanovinyl-1,4-DHP试剂的合成可能性很大14用四种活化的亚甲基作为亲核试剂进行了研究。顺序反应的关键步骤是基于有机碱催化的高度非对映选择性串联迈克尔加成反应/分子内氨基腈环化反应,从而以非对映选择性的方式形成了1,7-二氢吲哚并嗪。该方法似乎是一个简单的方法,可以扩展到许多活性亚甲基,如丙二腈,1,3-二酮和乙酰乙酸烷基酯。在室温下,用碱很容易完成部分氢化的吲哚嗪的1,3-氢转移反应,从而以非常好的收率得到相应的7,8-二氢吲哚并二氮。有趣的是,当活性亚甲基带有一个离去基团时,后一种方法无法完成,因为苯磺酸和亚硝酸的罕见顺式消除是在氢转移之前进行的。所得的1,7-二氢吲哚并带有并非在所有情况下都分离出C 1上的ex