4670
Vol. 83
CONMUNICATIONS TO THE EDITOR
others.? An explanation based on steric obstruction would predict a ratio CH3T/CF3T smaller than that of C H I T / C ( C H ~ ) ~from T neopentane; and one based on bond strength would predict that CH3T/ CF3T be unity since the strengths of the CH3-T and CFa-T bonds are virtually equal. The experiments showed a ratio CH3T/CF3T in excess of twenty, confirming the present model. Competition for capture of the hot atom is thus controlled by the same factor in attack on both C-C and C-X bonds: The availability of a strong bonding orbital within the time of collision, where this is governed by the inertia of the substituents on the central atorrts. This principle should be completely general for hot atom reactions but has no counterpart in therinal processes.
(shoulder). Reaction of IIa with ketene occurs exothermically to give 24% of heptafluorocyclobutyl acetate (IIIa), b.p. 99-101'. Anal. Found: C, 30.1; H, 1.4; F, 55.2.
-!-
IIa-IId
CH,=C=O
OCCHB
--+
IIIa, X = F, IIIc, X = Br IIIb, X = C1, IIId, X = I
In a similar manner, the alcohols 1Ib--IId were prepared by the addition of the appropriate hydrogen halide to I in 73-90% yields and these alcohols were converted to the corresponding acetate IIIbIIId in 3841% yields. Consistent elemental analySTERLING CHEMISTRY LABORATORY ses, infrared, FI9 and H ' n.1n.r. spectra were obYALEUNIVERSITY ROBERT ODUM tained for all of the products describedS2 N E W HAVEN, CONNECTICUT RICHARD WOLFGANG In the absence of moisture, all of the alcohols were RECEIVED SEPTEMBER 16, 1961 reasonably stable on storage except IId which slowly liberated iodine. At elevated temperatures, the equilibrium becomes unfavorable and the alcoa-HALO ALCOHOLS hols revert to some extent to ketone and hydsogen Sir : Mre wish to report the first preparation and isola- halide. This is a particular problem with I I a in tion of certain a-haloalcohols in pure form, and to glass apparatus since prolonged heating will condescribe some studies of hydrogen bonding in sume H F (shifting the equilibrium to the left) and these systems. Hexafluorocyclobutanone (I), an reaction of H F with glass produces water which also attacks the alcohol. Ketones and hydrogen halides ordinarily do not give stable addition Compounds.3 f 4 Vorlander obtained some unstable ketone-hydrogen halide complexes3 but the presence or absence of alcohol or ketone functions in these materials was not esI I1 tablished. In general, 1,l-halohydrins cannot be IIa, X = F isolated in pure form because of the rapid establishIIb, X=C1 ment of the addition-elimination IIc, X = B r IId, X = I For example, 2-chloro-2-~propanolcannot be isoIIe. X = O H lated from an acetone-HC1 mixtureGalthough 1: 1 F and 1: 2 acetone :RF nondescript complexes were IIf, % o b ; reported in 1SS3.6 F2 Previous attempts to prepare perfluorinated afluoroalcohols have been unsuccessfu1,7~8although extraordinarily reactive ketone,'" reacts rapidly at one example of an a-fluoroalcohol, monofluorolow temperatures with hydrogen halidesIb to give methanol, has been ~ e p o r t e d . ~ the distillable a-haloalcohols IIa-JId in high yields. Neither ring strain factors nos fluorine substituThus, equimolar quantities of I and hydrogen tion adjacent to the carbonyl function, alone, can fluoride were condensed in an evacuated Monel account for the stability of these a-haloalcohols vessel at -195". After allowing the mixture to relative to the ketones since neither a-fluorocyclowarm to +20°, distillation in a nitrogen atmos(2) Difficulties were encountered in obtaining good analytical values phere through a thoroughly dry glass column gave a I I I d . These data will appear in a future publicatiun. 75% yield of heptafluorocyclobutanol (IIa), b.p. f o r(3) D. VorlLnder, Atin., 341, 15 (1905). 57-58' (some dec.); b.p. 6" (85 mm.); Found: C, (4) W. Hhc!
