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VOL. 20 ~i t y .~ Since the tendency of amino compounds to form complexes with silyl groups with less than three Si-0 bonds is negligible,lO the effects seen here would be expected only in the case when R = (MeO)aSiCH2-Other possible interactions could involve intramolecular hydrogen bonding with the imino nitrogen and a silanol as in VI1 or silicon-oxygen bond formation with the 2-carbon atom of the ring (VIII). In the latter case the intermediate B would result after hydrolysis of the silicon-oxygen-carbon bond. These intermediates resemble those advanced to explain the enhanced rates of hydrolysis for certain a-keto phos-CHzCHz. (10) See, for example. C. Frye. G. E. Vogel, and J. A. Hall, J . Am, Chem. 6". , 88, 9913(1981).-Sl VI1 VI11 phate esters" and p-nitrophenyl salicylates.12 However, with such interactions all of the methoxysilanes studied should show effects similar to V unless an unusual acidity for the corresponding silanol of V is postulated to explain its unique behavior.Six additional representatives of the class of colored compounds, the bistetraphenylcyclopentadienones (l), have been prepared linked by (CHZ)~, (CHZ),, (CHZ)4, (CHZ)~, and (CH& respectively, and one in which one of the phenyl groups links two cyclopentadienone rings. New intermediates for their syntheses have been described including the required bisdeoxybenzoins and bisbenzils. Analogs of hexaphenylbenzene, melting in the range 337-470", were prepared from each bistetraphenylcyclopentadienone by reaction with tolan. The absorption spectra of bistetracyclones and bishexaphenylbenzenes have been discussed based on tetracyclone and hexaphenylbenzene as models.(7) G . M. Mkryan and N. A. Papazyan, Doki. Akad. Nauk Arm. SSR, 91,

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Trimethylox~sulfonium-~~C i o d i d e (30% 13C-enriched) was. prepared from l3C-labe1led barium carbonate by proceeding through methanol-13C and methyl-C iodide. t i o n of trimethyloxosulfonium i o d i d e which afforded 53.6% of product w a s modified so t h a t a 77% y i e l d of trimethyloxosulfonium-13C i o d i d e w a s obtained. 13The o r i g i n a l procedure f o r t h e prepara-