1110
-2.STREITWIESER, JR., D. P. STEVENSON AND U '. D. SCHAEFFEK
The compound was unaffected b>- lithium aluminum hydride in tetrahydrofuran a t room temperature. -4fter one hour of refluxing in the same solvent with a large excess of lithium aluminum hydride, 50% of the starting material \vas recovered unchanged. KO 1-(triphen)-lsilyl)-propan2-01 was detected.
Acknowledgment,-This research was supported in part by the United States Air Force under Contract -4.F 33(016)-3510 monitored by Xaterials
[JOIST
5'01.
s1
Laboratory, Directorate of Laboratories, \rright ~i~ ~ ~Center, \vright-patterson ~ ~XFR, Ohio. Infrared were obtained through the courtesy of the Institute for i!ltomic Research, Iowa State College. Special thanks are due to Dr. XT. A. Fassel, Mr. R. Kniseley and IIiss 1 1 . Powers for the spectra. AMES, IOWA
COMMCNICATIOX FROM THE DEPARTMENT O F CHEMISTRY, LriIVERSITY O F CALIFORNIA, AND THE SHELL
DEVELOPMENT CO.]
Boron Fluoride-Alcohol Alkylations
I. Benzene and the Amyl Alcohols
BY -4. STREITWIESER, JR., D. P. STEVENSON AND W. D. SCHAEFFER~ RECEIVED ALXXWT12, 1958 T h e alkJ-lation of benzene with alcohols and boron fluoride has been carried out with all eight amyl alcohols. Primary alcohols require several hours a t 60"; secondary alcohols react within minutes a t 0"; t-amyl alcohol gave no alkylation products at 0 " . Rearrangements are general. 2-Pentanol and 3-pentanol gave identical product mixtures containing 65c/, 2-phenylpentane, 25mo 3-phenylpentane and apparently about 10 yo of t-arnplbenzene. Neopentyl alcohol gave pure t-am ylbenzene
occurs without carbon skeleton rearrangement." The results of Hennion and Pieronik3' were presented with the implication that the boron fluoride alkylation of chlorobenzene with 2-pentanol yields 2-p-chlorophenylpentane and :3-pentanol yields 3P-chlorophenylpentane, etc., although Burwell, et u Z . , ~ ' found that "methoxypentane with boron fluoride and benzene yields a mixture of 737, of 2phenylpentane and 25y0 of 3-phenylpentane. In preparation for experiments designed to examine the mechanism of the reaction between aromatic hydrocarbons and alcohols and boron fluoride, we studied the behavior of all of the eight isonieric amy1 alcohols in this reaction. In the present work alkylations were run with large excess of benzene to minimize the production (1) Presented in part a t t h e 128th l l e e t i n g o f the American Chemical of dialkylated products. Generally, 10-20 g. of albociety, RZinneapolis, M i n n . , Sept. 11, 1955. This research was supcohol in 100 g. of benzene was saturated with boron Iiorted in p a r t b y a grant from the Petroleum Research F u n d administered by t h e American Chemical Society. Grateful acknowledgment fluoride and maintained a t an appropriate temperais hereby made t o t h e donors of this fund. ture. \Vith secondary alcohols reaction takes place ( 2 ) General Electric Fellow, 1955-1958. rapidly a t 0"; primary alcohols require several (3) (a) 1'. J. Sorva, G. F. Hennion and 1. A. Nieuwland. T H I S J o U K hours a t 60". Promoters such as phosphorus pents . ~ , 57, , 709 (lL435); (b) J. F. RIcKenna a n d F. J. S o w a , i b i d . , 69, 470 (1937); (c) 60, 13-1(19:38); (d) N . F. Toussaint and G. F. Hennion, oxide and sulfuric acid which have been used frei b i d . , 62, 1143 (1940); (e) C. C. Price and 51, L u n d , i b i d . , 63, 3105 quently in such alkylations were not used in our (1940); ( f ) C . E. a'elsh and G. F. Hennion, ;bid., 63, 2603 (1941); experiments to avoid any complicating factors (c) R.1,. Burwell, J r . , a n d S. Archer, i b i d . , 64, 1032 (1942); (h) D. which they may introduce. Small amounts of waSightingale, H . D. Radford a n d 0. G. Shanholtzer, i b i d . , 64, IO62 ter, however, were present in some cases; water is (1912); (i) G. F. Ilennion and V. R.Pieronik, i b i d . , 64, 2751 (1942); ( 3 ) G. I,. Hennion and L. A, A U S ~ O Sibid., , 65, 1603 (1943); (k) D. known to be a potent promoter r i g h t i n g a l e a n d J. I
