ISSN:
1042-7163
Keywords:
Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The reaction of a series of 4,4-dimethyl-3,5,5-(R3, R2, R1)-3-hydroxy-1,2-dioxolanes 1a-d [1a (R1 = R2 = R3 = Me); 1b (R1 = R2 = Me, R3 = Ph); 1c (R1 = Ph, R2 = R3 = Me); 1d (R1 = R3 = Ph, R2 = Me)] with trimethyl phosphite or triphenylphosphine produced the β-hydroxy ketones, 2a-d [(R1R2C(OH)CMe2-COR3)], and the corresponding phosphoryl compounds in high yield. The reactions were slow (∼24 hours), requiring excess of the trivalent phosphorus compounds for optimum results. The reaction was found to be of the second order overall, first order in peroxide and in phosphorus reagent. Triphenylphosphine was found to be more reactive than trimethyl phosphite. Formal substitution of a phenyl group for a methyl group on the hemiperketals yielded a reduction of reactivity of ∼2.4-fold at the 3-position but an increase in reactivity (∼1.5-fold) at the 5-position. The rate constants for tautomerization of 1c in benzene were determined. The activitation parameters for reaction of 1c with triphenylphosphine in benzened6 were determined [ΔH
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hc.520040209
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