From Cycloalkanols to Heterocycles via Nitrogen Insertion

A variety of cyclic alcohols are found to undergo nitrogeninsertionby subjection to O-mesitylsulfonylhydroxylamine.Critical to a successful process is the use of fluorinated alcoholicsolvents, which ensures sufficient substrate activation to allow engagementwith the ambiphilic aminating agent. This transition-metal-free nitrogeninsertion provides access to a variety of medicinally relevant heterocyclessuch as pyrrolidenes, quinolines, and benzazepines (24 examples).Furthermore, combination with a photochemical Norrish-Yang-typecyclization allows an unprecedented access to indoles from ortho-substituted acetophenones.

Automated summary

A variety of cyclic alcohols can be converted into medicinally relevant heterocycles by subjecting them to nitrogen insertion using O-mesitylsulfonylhydroxylamine. The use of fluorinated alcoholic solvents is crucial to activate the substrates and allow them to react with the ambiphilic aminating agent. This transition-metal-free reaction also provides an unprecedented access to indoles from ortho-substituted acetophenones when combined with a photochemical Norrish-Yang-type cyclization.