CARBETHOXYNITRENE . STEREOCHEMISTRY OF INTERMOLECULAR SINGLET CARBON-HYDROGEN INSERTION

Carbethoxynitrene inserts into the C-H bonds of 3-methylhexane with a selectivity that does not change over a concentration range from 100 to 1.2 mol % of the hydrocarbon. The selectivity is also unaffected by the presence of a triplet nitrene trap, α-methylstyrene, and by using a heavy atom solvent, dibromomethane, instead of dichloromethane. The insertion into the tertiary C-H bond of optically active 3-methylhexane proceeds with 100% retention of configuration, under all reaction conditions, and irrespective of the path by which the nitrene is generated. It is concluded that only the singlet state of carbethoxynitrene participates to a measurable extent in the insertion reaction. © 1969, American Chemical Society. All rights reserved.