REARRANGEMENT STUDIES WITH C¹⁴: XI. THE FORMOLYSIS OF 2-PHENYLETHYL-1-C¹⁴p-TOLUENESULPHONATE WITH OR WITHOUT ADDED SODIUM p-TOLUENESULPHONATE-S³⁵

Abstract

The formolysis of 0.350 M 2-phenylethyl-1-CL' p-toluenesulphonate (I) was carried out a t 7 4 f 0.2" C with or without the presence of at1 equirnolar amount of sodium p-toluenesulphonate-S3s ( [[I). The over-all hrst-order rate constant, k l , was found to be 2.6X10-j sec-1 and 3.0X10-s sec-I, respectively, for the reaction with and without added 111. The determination of the degrees of rearratigement of the C1"-labeled atoms from the C-1 to the C-2 positions in the 2-phetlylethyl p-toluenesulphonate (I,) recovered from the reaction mixture a t various reaction times permitted the evaluation of kL,', the rate of return from ionic intermediates to covalent bonding. Using the experimental data, it was possible to calculate k, and k~, the rates, respectively, for the anchimerically unassisted and assisted solvolysis. As expected, fortnolysis of 1 proceeded principally by the anchimerically assisted process. Calculations also showed that the fraction of the anchimerically assisted ionization r e t~~r n i n g t o covalent bonding was about 15% for the reaction in the presence of 111, while i l l the absence of 111, the return was about 9%. For the formolysis of I in the presence of 111, the extents of incorporati011 of S3j in the recovered sulphonate I, were also determined. The S3j incorporation in I,, when considered in conjunction with the CL" rearrangement in I,, led to the conclusion that the ret~lrn from ionic intermediates to covalent bonding during the fortnolysis of I included both internal and external returns, the extent of external return being the greater of the two. INTRODUCTIONIn earlier publications (1, 2), isotope position rearrangements observed in the solvolysis of 2-phenylethyl-1-C14 P-toluenesulphonate (I) under various conditions were reported.When acetolysis and forinolysis of I were interrupted a t about 50y0 completion, the rearrangement of C14-labeled atoins from the C-1 to C-2 positions in the recovered 2-phenylethyl-x-C14 p-toluenesulphonate (I,) indicated some return to covalent bonding through the intermediate ethylphenoniuill ion (11) or its equivalent. Solvolysis of I in the presence of sodium p-toluenesulphonate-S35 (111) made possible the simultaneous determinations of C14 rearrangeinent and S35 incorporation in the sulphonate I, recovered from the partially solvolyzed mixture. The data obtained for fornlolysis (2) indicated that some of the p-toluenesulphonate anions involved in the return to give the isotopically rearranged 2-phenylethyl-2-C1" p-toluenesulphonate were derived froin an intrainolecular process, thus pointing to the occurrence of some interllal return from an intinlate ion pair (3-6) during the forinolysis of I.'ilfa?zzcscript received itlarch 16, 1961.

Decomposition of a phosphoryl azide adduct of norbornylene

“…spectra with the sample prepared as described above. 3This coupling is that expected for P-N-C-H coupling for a phosphorylated aziridine (6 …”

Rearrangement studies with 14C. XXXII. Solvent effects in the solvolyses of 2-phenyl-1-14C-ethyl tosylate and 2-phenyl-1-14C-ethylmercuric perchlorate

“…In solvolyses involving the 2-phenyl-l-l4C-ethyl system, as far as product formation is concerned the net results may be considered as arising from a unimolecular process with rate constant kA via the ethylenephenonium ion, or its equivalent of a pair of rapidly equilibrating 2-phenylethyl cations, which would give rise to 50 % 14C-rearrangement, and a direct displacement process with specific rate constant k, which would give a product without rearrangement (1,6). When the contribution from the kA component is high, much of the reaction would lead to products accompanied by rearrangement and the overall extent of rearrangement would be relatively insensitive to changes in Y.…”