COMMUNICATIONS
The Oxidation of Epoxides by Dimethyl Sulfoxide. A Simple Synthesis of a-Hydroxy Ketones'
Sir:
1681
In a simi!ar manner, both 2P,3P-epoxy-5acholestane and 2a,3a-epoxy-5a-cholestnne (dioxane was required as a co-solvent in the latter case) gave 5a-cholestane-3p-ol-2-one, l o m.p. 105.5-107', in yields of 55% and 45%, respectively." In addition, both epoxides afforded 5a-cholestane-2,3dione,I2 m.p. 138-140" (11% and 19%, respectively) and 5a-cholestane-2P,3a-diol,'g m.p. 200201' (10% and 5%, respectively). Phenacyl alcohol was prepared in 57% yield from styrene oxide by the same procedure.
Dimethyl sulfoxide reacts with primary and secondary alkyl halides and tosylates to yield the corresponding aldehydes and ketones respectively. 2--8 We should now like to report that epoxides can also be oxidized by dimethyl sulfoxide if catalytic CONTRIBUTION No. 1080 THEODORE COHEN DEPARTMENT OF CHEMISTRY TADAKAZU TSUJI quantities of boron trifluoride are present. In UNIVERSITY OF PITTSBURGH accord with the results obtained with halides and PITTSBURGH 13, PA. tosylates, the products are a-hydroxy ketones and Received February 10, 1961 dimethyl sulfide. Although the same reaction occurs in the absence of catalyst, much longer reaction An apparently pure sample of dimer, map. 151-152', periods are required and the yields are seriously has(9)been obtained by recrystallization of this mixture from reduced. A sample procedure is described. acetone. Its elemental analysis, determined molecular A solution of 10.0 g. (0.102 mole) of cyclohexene weight, infrared spectrum and its ready conversion to the oxide and 0.12 ml. of boron trifluoride etherate in osazone of the monomer are all consistent with the dimeric 40 ml. of dimethyl sulfoxide (predried by azeo- structure. J. C. Sheehan and W. F. Erman, J . Am. Chem. Soc., tropic distillation with benzene) was heated on a 79.(10) 6050 (1957). steam bath for 22 hr. Additional portions (O.OG (11) Assuming diaxial ring opening by dimethyl sulfml. and 0.04 ml.) of catalyst were added a t the oxide, the 8- and a-epoxides would be expected to yield, end of 15 and 20 hr., respectively. The reaction respectively, 5a-cholestan-2~-01-3-onc and 5a-cholestanThese are presumably converted via a common mixture was poured into ice water and extracted 3a-ol-2-one. enol intermediate to the more stable10 hydroxyketone with chloroform. Evaporation of the dried extracts actually isolated. and distillation of the residue furnished 8.8 g. (76y0 (12) E. T. Stiller and 0. Rosenheim, J . Chem. Soc., 353 yield) of 2-hydroxycyclohexanone as a colorless oil, (1938). (13) R. E. Marker and L. Plambeck, Jr., J . Am. Chem. b.p. 83-85"/13 mm.; reported' b.p. 71'/7 mm. This substance was further identified (1) by com- Soc., 61, 1332 (1939). parison of its infrared spectrum with that reported,' (2) by the formation of its o s a z ~ n e , ~ ~ ~ The Reaction of Aminomethyltrimethylm.p. 218" dec., and (3) by its solidification to n variable melting range mixture of monomer and silane with Nitrous Acid' I n one run, dimethyl sulfide, 11.p. 36-38', was obtained in 60% yield by distillation of the Sir: reaction mixture prior to work-up. The well known reaction of nitrous acid and (1) This work was sponsored by the United States Air aliphatic amines is characterized by products Force under Contract No. AF 49(638)-788 monitored by resulting from an intermediate carbonium ion. We the AF Office of Scientific Research of the Air Research wish to report that the reaction of aminomethyland Development Command. (2) K. Kornblum, J. W. Powers, G. J. Anderson, W. J. trimethylsilane hydrochloride (I) and nitrous acid Jones, H. W. Larson, 0. Levand, and W. M. Weaver, results in silicon-carbon bond cleavage. Apparently J . Am. Chem. SOC.,79, 6562 (1957). diazomethane, rather than nitrogen, is the leaving (3) N. Kornblum, W. J. Jones, and G. Anderson, J. A m . group. No products which would result from carChem. SOC.,81, 4113 (1959). bonium ion 112could be detected. (4) H. R. Xace and J. J. Monagle, J. Org. Chem., 24, 1792 (1959). . 2 5 , 670 (1960). (5) M. M. Baker, S. 0 ~ g Chem., (6) I. M. Hunsberger and J. M. Tien, Chem. & Ind., 85 (1959). (7) J. C. Sheehan, R. C. O'Neill, and M. A. White, J . A m . Chem. SOC.,72, 3376 (1950). (8) H. Adkins and A. G . Rossow, J . A m . Chem. SOC., 71, 3836 (1949).
(1) This work was supported by a grant (NSF-G14554) from the National Science Foundation. (2) The conversion of chloromethyltrimethylsilane to ethyldimethylchlorosilane with aluminum chloride is poetulated as proceeding through I1 [F. C. Whitmore, L. €1. Sommer, and J. R. Gould, J . Am. Chem. Soc., 69, 197G (1947)].
