ANRORCRearrangement

Abstract

ANRORC rearrangement is a very common transformation for heterocycles, and has been discovered for more than a century already. It occurs in nucleophilic substitution of heterocyclic compounds, and stands for a whole process of the initial addition of a nucleophile, followed by the ring opening and ring closure during the substitution. This transformation is also known as S N (ANRORC) reaction or degenerate ring transformation. This reaction has been reported to consist two subgroups with either an “outside” leaving group or “inside” leaving group. This rearrangement reaction has wide applications in heterocycle chemistry.

Thermal Rearrangement of 5-(2-Hydroxy-6-oxocyclohexyl)-5H-chromeno[2,3-b]pyridines

“…The following ANRORC (Addition of the Nucleophile, Ring Opening, and Ring Closure) mechanism of the thermal rearrangement of chromeno[2,3- b ]pyridines 1 into 5,7-dihalogenated 5-(2,3,4,9-tetrahydro-1 H -xanthen-9-yl)-6-oxo-1,6-dihydropyridines 2 and 10-(3,5-dihalogen-2-hydroxyphenyl)-5,6,7,8,9,10-hexahydrobenzo[b][1,6]naphthy-ridines 3 ( Scheme 5 ) was proposed based on the literature data [ 21 , 31 ].…”

“…ANRORC rearrangement occurs in the nucleophilic substitution of heterocyclic compounds and represents a process of the subsequent Addition of the Nucleophile, Ring Opening, and Ring Closure in the same molecule [ 20 , 21 ]. These rearrangements have been studied extensively [ 22 ].…”