MECHANISM OF &ALKOXY ALDEHYDESFROM WZ-DIOXANES
Sept. 5 , 1962
3319
The desired ethyl methallyloxypivalate was obtained in tion is probably the 2 : 1 adduct resulting from addition of only 17% yield, b.p. 91-94.5" (16 mm.); the later fraction, this new acetal to a second mole of vinyl ether, and if so, b.p. 94.5' (16 mm.), had W ~ 1.4268, ~ D dB525 0.9203, M R its formation could be suppressed by use of a larger excess of diethyl formal. The redistilled 1:1 adduct, b.p. 100" 55.77 (calcd. 52.85). Anal. Calcd. for CllH2003: C, 66.0; H , 10.0. Found: (33 mm.), ?ZZ5D1.4100, was analyzed. Anal. Calcd. for C U H ~ ~ O C,~64.66; : H, 11.84. Found: C, 65.9,66.1; H , 10.2, 10.2. C, 64.8,64.7; E€, 11.6,11.4. The unsaturated ester was hydrogenated in methanol A sample was exposed to the Johnson D X P reagent1* a t atmospheric pressure over platinum oxide. The reducand yielded ethoxypivalaldehyde 2,4-dinitrophenylhydration was complete in 15 minutes. Most of the methanol was removed from the filtered solution, and the residue was zone identical with that prepared from aldehyde obtained refluxed with methanolic potassium hydroxide for 2.75 by pyrolysis of acetal 3. A second sample was hydrolyzed15 hours. The acid was isolated by evaporating the methanol, to ethoxypivalaldehyde, the physical properties and inacidifying, and extracting with ether. Isobutoxypivalic acid frared spectrum of which were identical with those of the was obtained in 55% yield, b.p. 78" (0.9 mm.), ?ZZ5D1.4200, pyrolysis product. &Idditionof dimethyl formal to ethyl isobutenyl ether in d2%,0.9472. the presence of boron fluoride etherate led to a complicated
