Syntheses of α,β-Unsaturated Carbonyl Compounds from the Reactions of Monosubstituted Ozonides with Stable Phosphonium Ylides

A short and efficient synthesis of α-C-(1 → 3)-linked disaccharides containing deoxyhexopyranoses

“…We have found that when starting with the easily accessible peracetylated a-D D -glucopyranosylprop-2-ene 1, it is not necessary to isolate the arising aldehyde 3, as the intermediary ozonide can be decomposed directly with the thiazole ylide 5, analogously as already described for decomposition of ozonides with other stabilized ylides. 21 In this way, we converted the starting compound 1 into trans-oxadiene 6 in 75% yield without isolating aldehyde 3. Further synthetic steps, consisting of cycloaddition, deacetylation and finally benzylation of the mixture of cycloadducts 8 and 9 (see Scheme 1), afforded a chromatographically well separable 1:1 mixture of diastereoisomers 10 and 11.…”

Transformations of peroxide products of olefins ozonolysis

“…75 The addition of catalytic quantity of p-toluenesulfonic acid to the peroxide ozonolysis products of cycloolefi ns 16 in acids resulted in the formation of ω-dialkoxy-α-alkoxyhydroperoxides 35. The neutralization of the catalyst with sodium hydrogen carbonate followed by the treatment with dimethyl sulfi de furnished the target ω-dialkoxyaldehydes 83 [12].…”

“…By the reaction of monosubstituted ozonides 162 prepared from terminal alkenes with a slight excess of stable phosphonium ylides without additional reducers α,β-unsaturated esters 163 were obtained in high yields [75] (Scheme 29).…”

Structural Effects in Radical Clocks and Mechanisms of Grignard Reagent Formation: Special Effect of a Phenyl Substituent in a Radical Clock when the Crossroads of Selectivity is at a Metal/Solution Interface

“…A column of silica gel (petroleum ether/EtOAc 97:3) followed by a separation on silica gel impregnated with AgNO 3 (petroleum ether/EtOAc 98:2) afforded 5 as a colourless oil (0.09 g, 61 %, Z/E 91:9 1 H NMR (300 MHz, CDCl 3 ): δ = 2.43 (q, J = 7.6 Hz, 2 H), 2.86 (t, J = 7.6 Hz, 2 H), 6.13 (t, J = 7.6 Hz, 1 H), 7.00-7.36 (m, 13 H), 7.49 (dd, J = 7.9, 1.1 Hz, 1 H) ppm. 13 [115] (1,4-Diphenylbut-1-enyl)benzene (3l) and 1-(Diphenylmethyl)-2,3-dihydro-1H-indene (3c): Chromatography on AgNO 3 -impregnated silica gel (petroleum ether) afforded 3l and 3c as colourless oils. (24).…”