PSEUDOHALOGENS .11. IN SITU ADDITION OF NITROSYL FORMATE TO OLEFINS

Nitrosyl formate, the lowest homolog of the nitrosyl acylate series, has been prepared in situ from isoamyl nitrite and formic acid and added to a number of acyclic-, alicyclic-, and aryl-substituted unsaturated compounds to yield novel, reactive formoxynitroso compounds. Addition proceeds best with olefins activated electronically (styrene, a- and /3-methylstyrene) or sterically (norbornene, cyclohexene) toward electrophilic addition and poorly or not at all with mono- or disubstituted olefins. Markovnikov addition products are obtained. When the nitroso group becomes attached to a tertiary carbon atom, as in the adducts of 2,3-dimethyl-2-butene and Δ9-octalin, products are blue monomers; in all other cases the products are colorless dimers. Monomeric 2,3-di-methyl-2-formoxy-3-nitrosobutane has the typical esr spectrum of a monoradical. Addition of nitrosyl formate to norbornene yields the exo-cis adduct without rearrangement, presumably by a four-center reaction. Addition to cyclohexene proceeds by trans addition. Further reactions of some of the nitrosyl formate addition products are described. Preliminary results of the addition of nitrosyl acetate and benzoate to unsaturated compounds are also discussed. © 1968, American Chemical Society. All rights reserved.