Diprotonative stabilization of ring-opened carbocationic intermediates: conversion of tetrahydroisoquinoline to triarylmethanes
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. This journal is
Kurouchi, Hiroaki
p. 8313 - 8316
(2020/08/17)
Isoquinoline-N-Boranes as Precursors to Substituted Tetrahydroisoquinolines
A new approach to the syntheses of 1,2-disubstituted 1,2,3,4-tetrahydroisoquinolines from isoquinoline-N-boranes is described.The method is a "one-pot" operation in which substituents are introduced consecutively as electrophiles and nucleophiles with accompanying reduction of the heterocyclic ring.This procedure differs from the classical ones in that both requisite rings are present in the starting material and thus avoids the inefficient cyclizations of phenethylamine derivatives when unactivated substrates would be required.The synthetic utility of this process is demonstrated with several examples including the alkaloids carnegine and hydrohydrastinine.
Brooks, Donald J.,Dowell, David S.,Minter, David E.,Villarreal, Mark C.
p. 130 - 133
(2007/10/02)
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