Rhodium(II)-catalyzed alkyne amination of homopropargylic sulfamate esters: stereoselective synthesis of functionalized norcaradienes by arene cyclopropanation.

ABSTRACT

A rhodium(II) catalyzed nitrene-alkyne cycloaddition of stereochemically well-defined homopropargylic ethers is followed by arene cyclopropanation to afford unique tetracyclic norcaradiene products bearing a cyclic sulfamate. Products from the arene cyclopropanation (Buchner reaction) can be converted to fused cycloheptatrienes via a ring enlarging electrocyclization after nucleophilic ring opening of the cyclic sulfamate ester.