title: Rearrangements concerted with fragmentation of cyclopropylmethoxychlorocarbene and cyclobutoxychlorocarbene in hydrocarbon solvents and Ar matrices.
abstract: Fragmentations of cyclopropylmethoxychlorocarbene (6) and cyclobutoxychlorocarbene (10) lead to rearrangments that afford mixtures of cyclopropylmethyl chloride (7), cyclobutyl chloride (8), and 3-butenyl chloride (9). Isotopic substitution studies show that these rearrangments are accompanied by partial exchange of the methylene groups within 6 and 10. Surprisingly, these processes that are typical of carbocations persist in hydrocarbon solvents such as pentane and cyclohexane-d(12). Quantum chemical calculations reveal that the cis-conformers of the incipient oxychlorocarbenes C(4)H(7)OC(..)Cl decay to C(4)H(7)Cl + CO via transient hydrogen bonded C(4)H(7)(delta)(+)...Cl(delta-) complexes which possess significant ion pair character, even in the gas phase or in nonpolar solvents. In contrast to benzyloxychlorocarbene, no free radicals are formed upon generation or photolysis of 6 or 10 in Ar matrixes, although acid chlorides (the recombination products of these radical pairs) are observed. The IR spectra obtained in these experiments show the presence of several conformers of the two C(4)H(7)OC(..)Cl.
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA. moss@rutchem.rutgers.edu
authors.forename: Robert A
authors.initials: RA
authors.lastname: Moss
authors.forename: Ronald R
authors.initials: RR
authors.lastname: Sauers
authors.forename: Fengmei
authors.initials: F
authors.lastname: Zheng
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Fu
authors.forename: Thomas
authors.initials: T
authors.lastname: Bally
authors.forename: Alexander
authors.initials: A
authors.lastname: Maltsev