Diprotonative stabilization of ring-opened carbocationic intermediates: conversion of tetrahydroisoquinoline to triarylmethanes
作者:Hiroaki Kurouchi
DOI:10.1039/d0cc01969k
日期:——
Superacid-promoted conversion of tetrahydroisoquinolines to triarylmethanes via tandem reactions of C–N bond scission, Friedel–Crafts alkylation, C–O bond scission, and electrophilic aromatic amidation was developed. Dication formation was important for stabilizing the ring-opened carbocationic intermediate, which is a new role for diprotonation in reaction mechanisms.
Enhancement of the carbamate activation rate enabled syntheses of tetracyclic benzolactams: 8-oxoberbines and their 5- and 7-membered C-ring homologues
作者:Hiroaki Kurouchi
DOI:10.1039/d0ob02096f
日期:——
A route to the direct amidation of aromatic-ring-tethered N-carbamoyl tetrahydroisoquinoline substrates was developed. This route enabled general access to 8-oxoberberines and their 5- and 7- membered C-ring homologues. It overcomes the undesired tandem side-reactions that result in the destruction of the isoquinoline backbone, which inevitably occurred under our previously reported superacidic carbamate