Acetone 1,3-diphenyl substituted

Disilenes react with ketones, aldehydes, esters and acid chlorides by formal [2 + 21-cycloaddition to yield the corresponding disiloxetanes (equation 73)8,16. The reaction is non-concerted and proceeds through the initial formation of a 1,4-biradical intermediate, as has been shown by the products of reaction of tetramesityldisilene (110) with the cyclopropyl aldehyde 117 (equation 90)163. The absolute rate constants listed in Table 19 indicate there to be a significant difference in reactivity between the monophenyl-substituted disilene 103 and the 1,2-diphenyl-substituted derivatives 104, consistent with a steric effect on the rate of formation of the biradical intermediate. As would be expected, no kinetic deuterium isotope effect is discernible from the relative rates of addition of acetone and acetone- to these compounds. 

Substituted hydrazines yield the corresponding substituted in-dols for example, from diphenylliydrazine and acetone diphenyl-indol is formed ... 

A number of related reactions are worthy of mention. Benzanilide (334) is converted into phenanthridone (335) by irradiation in benzene in the presence of iodine.362 Cyclodehydrogenation is also observed in the anilides of indole-2-carboxylic acid and indole-3-carboxylic acid on irradiation in acetone.363 Irradiation of diphenyl-amine304 and certain of its JV-substituted derivatives365 yields the corresponding carbazole. The mechanism of this reaction differs from... 

The absolute rate constants for ene-addition of acetone to the substituted 1,1-diphenyl-silenes 19a-e at 23 °C (affording the silyl enol ethers 53 equation 46) correlate with Hammett substituent parameters, leading to p-values of +1.5 and +1.1 in hexane and acetonitrile solution, respectively41. Table 8 lists the absolute rate constants reported for the reactions in isooctane solution, along with k /k -, values calculated as the ratio of the rate constants for reaction of acetone and acctonc-rff,. In acetonitrile the kinetic isotope effects range in magnitude from k /k y = 3.1 (i.e. 1.21 per deuterium) for the least reactive member of the series (19b) to A hA D = 1.3 (i.e. 1.04 per deuterium) for the most reactive (19e)41. Arrhenius plots for the reactions of 19a and 19e with acetone in the two solvents are shown in Figure 9, and were analysed in terms of the mechanism of equation 46. 

The mobile chlorine atoms in the CICH2 groups can easily be substituted with iodine by boihng the chloromethylated polymer with twofold molar excess of sodium iodide in a mixture of acetone and dioxane (3 1, v/v) [378]. A polymer with an 83% degree of iodomethylation was thus obtained on the base of a macronet isoporous matrix prepared by post-crosshnking of a styrene-0.8% DVB copolymer with 11% additional bridges formed by 4,4 -bis (chloromethyl) diphenyl. 

Treatment of 2,2-dimethyl-1,3-dioxepane with carboxylic acids results in the formation of tetra-hydrofuran and acetone <6UOC4762>. Acid-catalyzed hydrolysis of methyl-substituted 2,2-diphenyl-... 

The first example of the use of L-proline amino alcohol amides was reported by Gong and coworkers. The reaction between various substituted aldehydes and acetone is mediated by catalyst 30, which was previously prepared from L-proline and (l5,2S)-diphenyl-2-aminoethanol, and gave the desired hydro g ketones in excellent enantioselectivity and moderate to good yields (Scheme 13.20a). Additionally, quantum mechanical calculations of the transition structures of the model reaction revealed that hydrogen bonding between the peptide, mediated by amide N-H and the terminal... 

There has been a fuller account given of the formation of the 2,2 -anhydro-system 18 ftom the 2, 3 -ene by treatment with N-bromoacetamide (see Vol. 26, p. 227). Treatment of 18 with NaOH in acetone formed the D-Zyro-epoxide 19. When the xylose-derived nucleoside 20 was treated with diphenyl carbonate and NaHCOs, the 2,2 -anhydronucleoside 21 was obtained, and it was proposed that the mechanism of this process proceeded through the 3 ,5 -cyclic carbonate and the 2, 3 -ribo-epoxide as intermediates. Treatment of 21 with pyridinium bromide followed by hydrogenolysis gave thymidine. The oxazoline 22 can be used as a precursor of various 5-substituted 2,2 -anhydrouridine derivatives, as in the case shown in Scheme 2. The... 

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