Stereoselectivity of cyclisations via N-acyliminium ions to form pyrido[2′,3′:3,4]pyrrolo[2,1-a]isoindole, -isoquinoline and -benz[c]azepine ring systems
作者:Abood A. Bahajaj、John M. Vernon、Giles D. Wilson
DOI:10.1039/b009316p
日期:——
Pyrido[2′,3′:3,4]pyrrolo[2,1-a]isoindole, -isoquinoline and -benz[c]azepine derivatives are obtained by heating in polyphosphoric acid (PPA) appropriate hydroxy lactam precursors derived from pyridine-2,3-dicarboximides. The stereoselectivity of ring closure is rationalised by considering the development of A(1,3) strain in the cyclisation step from N-acyliminium ion intermediates.
吡啶并[2',3':3,4]吡咯并[2,1-一个]异吲哚,异喹啉和苯并〔C ^ ]是通过在多磷酸中加热得到的氮杂衍生物(PPA)适当羟基内酰胺的前体从吡啶衍生2,3-二甲酰亚胺。通过考虑在环化步骤中由N-酰基酰亚胺离子中间体形成A(1,3)菌株,可以合理地实现闭环的立体选择性。