G. J. KARABATSOS, C. E. ORZECH, JR.,
1994 [CONTRIBUTIOS FROM
THE
S. MEYERSON
AND
Vol. 86
KEDZIECHEMICAL LABORATORY, MICHIGAN STATE UXIVERSITY, EASTLASSISG,MICH, A I - D AXD DEVELOPMENT DEPARTMEST, AMERICANOIL Co , WHITING,I N D]
Carbonium Ion Rearrangements. VI.
THE
RESEARCH
Mechanism of the Rearrangement of Neopentyl Compounds
BY GERASIMOS J. KARABATSOS,'~ CHESTERE. ORZECH, JR
, I b AND
SEYMOUR MEYERSON'~
RECEIVEDDECEMBER 17, 1963 The t-amyl alcohols obtained from the deamination of neopentyl-l-13C and neopentyl-l,l-d2-amines,from the solvolysis of neopentyl-l-13C and neopentyl-l,l-dZ tosylates, and from the solvolysis of n e ~ p e n t y l - l - ' ~ C iodide were analyzed by n.m.r. and mass spectrometry. Also analyzed by n.m.r. was the t-amyl chloride obtained from the reaction of neopentyl-l-13C alcohol with triphenyl phosphite and benzyl chloride. The label originally present a t C-1 of the neopentyl compounds always ends up a t C-3 of the t-amyl compounds. The results rule out the intervention of 1,3-hydride shifts, protonated cyclopropanes, or hydrogen-bridged ions during the rearrangement.
The intermediacy of cationated cyclopropanes in gas-phase ionic decompositions in the mass spectrometer is well documented.2 The suggestion3 that such species may intervene as intermediates in liquid phase carbonium ion rearrangements, however, has not been substantiated. Conversion of the neopentyl group to the t-amyl group by the reaction of neopentyll-13C alcohol with hydrogen bromide4 or by deoxideation of neopentyl- l,I-& alcohol5 proceeds with no perceptible intervention of protonated cyclopropanes. Nevertheless, the recently reported 1,3-hydride shifts6,' and proton exchange between cyclopropane and sulfuric acid* might be interpreted in terms of protonated cyclopropanes, either symmetrical (I) or hydrogen bridged (11).
