COMMUNICATIONS TO THE EDITOR
3158
either may be too small in intensity to be seen or may be absent entirely. From this consideration it would seem t h a t B7HI3is a likely formula. The possibility of a B7 compound has been mentioned previously from mass spectral d a t a 3 but no pattern or formula was reported because of the masking effect of higher boranes present. After submission of this communication, our attention was called to a report of Professor Riley Schaeffer at the Boston meeting of the American Chemical Society (April 6-10, 1959) t h a t he had evidence for a heptaborane. H e reported mass peaks up to 91 with a minimum formula B7H14 and, therefore, suggested t h a t the hydride may be B7Hl5,
ates have an intermediate p value (Table I) indicating t h a t the cyclopropane ring is better than a dimethylene group b u t poorer than an ethylenic unit in transmitting electronic effects. This is in agreement with the dipole moment work but a t variance with the data obtained from ionization constants. In Table I the p values for the ionization of the acids and for the alkaline hydrolysis of the esters are compared. I n Table 11 are the rate constants for four ethyl trans-2-phenylcyclopropanecarboxylates prepared from acids which have the same physical constants as those previously rep0rted.j TABLE I COMP~4RISONO F KEACTIOX CONSTASTS p-Ester +Acid Series hydrolysis ionization
(:3) R . E Uickerson, P. J. lVheatle>-, P. A . Howell and lV. S . Lipscomb. J . Cheiii. P h j z , . 27, 200 (195i).
DEPARTMEST OF CHEMISTRY
REXSSELAER POLYTECHSIC 1SSTITUTE
truns- Ciiiiiainic trc~ns-2-Plieiiylc~clopropalle
ROBERTIT.SCHAEFER
KESNETHH. LUDLUM STEPHES E. WIBERLFY RECEIVED APRIL 10, 1959
TROY, SEIV YORK
TRANSMISSION OF ELECTRONIC EFFECTS BY T H E CYCLOPROPANE RING. RATES O F ALKALINE HYDROLYSIS O F S O M E ETHYL +SUBSTITUTED 2-PHENYLCYCLOPROPANECARBOXYLATES
( 1 1 See, for examlile, IV, IT'. Rohertsi3n J 1;. Llusic a n d 1.'. A. Xlatsen. THISJ O U R N A I - . 7 2 , J2ii0 (1930); G W. C a n n o n , A . A . Santilli a n d P. Shenian, ibid., 81, lfiO0 (1959). and references therein ( 2 ) L. I. Smith a n d E. R . Rogier, i b i d . , 73, 38-10 (1951); R . €1. IZastman a n d S . K . Freeman. z b i d . , 77, Gii.12 (1955), and preceding papers. i:3) R. I . Sl)inrad, ibici.. 68, G17 i l Y - l ! i ) , 11. T . Rogers and J . D . lioherts, %bid.. 68, 843 ( 1 9 4 t i ) . (4) R. W. Kierstead, R . P. Linstead a n d B . C .I
