Cocks,Frey

, p. 7583 (1969)

Fragmentation of cyclobutoxychlorocarbene: The cyclopropylcarbinyl/cyclobutyl cations revisited

Moss, Robert A.,Zheng, Fengmei,Johnson, Lauren A.,Sauers, Ronald R.

, p. 400 - 406 (2001)

Fragmentations of cyclobutoxychlorocarbene (13, kfrag= 7.1 × 105 s-1) and cyclopropylmethoxychlorocarbene (14, kfrag = 7.6 × 105 s-1) in MeCN proceed to tight and distinct [R+ OC Cl-] ion pairs, which collapse to different distributions of cyclopropylcarbinyl, cyclobutyl and allylcarbinyl chlorides. B3LYP/6-31G* calculations support these conclusions, affording computed fragmentation activation energies of 6.4 (13) and 3.0 (14) kcal mol-1.

Rearrangement, nucleophilic substitution, and halogen switch reactions of alkyl halides over NaY zeolite: Formation of the bicyclobutonium cation inside the zeolite cavity

Franco, Marcelo,Rosenbach Jr., Nilton,Ferreira, Glaucio B.,Guerra, Antonio C. O.,Kover, W. Bruce,Turci, Cassia C.,Mota, Claudio J. A.

, p. 1592 - 1600 (2008)

Rearrangement and nucleophilic substitution of cyclopropylcarbinyl bromide over NaY and NaY impregnated with NaCl was observed at room temperature. The first-order kinetics are consistent with ionization to the bicyclobutonium cation, followed by internal return of the bromide anion or nucleophilic attack by impregnated NaCl to form cyclopropylcarbinyl, cyclobutyl, and allylcarbinyl chlorides. The product distribution analysis revealed that neither a purely kinetic distribution, similar to what is found in solution, nor the thermodynamic ratio, which favors the allylcarbinyl halide, was observed. Calculations showed that bicyclobutonium and cyclopropylcarbinyl carbocations are minimal over the zeolite structure, and stabilized by hydrogen bonding with the framework structure. A new process of nucleophilic substitution is reported, namely halogen switch, involving alkyl chlorides and bromides of different structures. The reaction occurs inside the zeolite pores, due to the confinement effects and is an additional proof of carbocation formation on zeolites. The results support the idea that zeolites act as solid solvents, permitting ionization and solvation of ionic species.

Rearrangements concerted with fragmentation of cyclopropylmethoxychlorocarbene and cyclobutoxychlorocarbene in hydrocarbon solvents and Ar matrices

Moss, Robert A.,Sauers, Ronald R.,Zheng, Fengmei,Fu, Xiaolin,Bally, Thomas,Maltsev, Alexander

, p. 8466 - 8476 (2004)

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-d12. Quantum chemical calculations reveal that the cis-conformers of the incipient oxychlorocarbenes C 4H7OCCl decay to C4H7Cl + CO via transient hydrogen bonded C4H7 σ+...Clσ- 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 C4H7OCCl.

Durig,Morrissey

, p. 4854 (1967)

-

Olah,Lin

, p. 6468 (1968)

-

A Convenient Large-Scale Synthesis of Cyclobutyl Halides

Dupont, Andrea C.,Audia, Vicki H.,Waid, Philip P.,Carter, J. Paul

, p. 1011 - 1021 (2007/10/02)

An improved method for the preparation of multigram quantities of cyclobutyl halides is described.The Grignard reactivity of these halides is also discussed.