A formal (3+2) cycloaddition strategy toward 2-azanorbornanes

01 July 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Reported herein is the development of a photochemical method which allows for the construction of 2-azanorbornane scaffolds from cyclopropylsulfonamide derivatives. Access to the amine radical cation of these species is promoted by a Lewis acid additive which enables the ring opening of the cyclopropylamine moiety to initiate a cascade radical cyclization sequence. Notably, the method allows access to substituted 2-azanorbornane derivatives at all possible carbon centers and A1,3 stereocontrol is observed for C3 substituted derivatives. Preliminary mechanistic investigations suggest an integral role for the Lewis acid additive in facilitating single-electron transfer and avoiding deleterious dealkylation of the starting material. Thus, this method constitutes a modular, mild, and operationally simple approach to privileged saturated aza-heterocycles.


Photoredox catalysis
amine radical cation
cyclopropyl ring opening
saturated amines
cascade radical cyclization


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