Dioxolanes 4-alkyl-2-phenyl

S, 5S, JS)-2-[( 1-Benz yloxyamino)alkyl -4,5-bis[methoxymethyl -2-phenyl-l J-dioxolane ... 

Furthermore, it has been demonstrated in acetals of phenyl alkyl ketones that the presence of the aromatic moiety at the anomeric carbon induces a further stabilization resulting in very strong anomeric stabilization.29 This phenomenon is reminiscent of the stronger methyl substitution effects discussed above for 1,3-dioxolane and 1,3-dioxane (see also Table 1) than for alkyl ethers and alkanes. 

In several cases A-hydroxyphthalimide has been used as an organic mediator for the oxidation of alcohols to ketones, of benzyl ethers to benzoates , of alkyl aromatics to aryl ketones , and of 4-phenyl-l,3-dioxolanes to unprotected ketones... 

The photoaddition of alkanes onto electron-poor alkynes (e.g., propiolate or acetilendicarboxylate esters) can be accomplished by a radical conjugate addition reaction [7]. Radicals have been generated either via hydrogen abstraction from cycloalkanes or via electron transfer from 2-alkyl-2-phenyl-l,3-dioxolanes. In the first case, the irradiation was pursued on an alkane solution of an aromatic ketone (used as the photomediator) and the alkyne. Under these conditions, methyl propiolate was alkylated upon irradiation in the presence of 4-trifluoromethylacetophenone to form acrylate 48 in 97% yield (E/Z= 1.3 1 Scheme 3.31) [78]. 

Oxathiolanes and 1,3-dioxolanes containing a 2-phenyl substituent react with alkyl-lithium reagents to produce aryl alkyl ketones and alkenes (65JOC226). The mechanism of this reaction is discussed in Section 4.30.2.2.7. 

V an Gestel etal. 980) prepared a series of substituted 1 -(2-phenyI-1,3-dioxolan-2-yl-methyl)-1,2,4-triazoles (60), ana evaluated them in the greenhouse for fungicidal activity. Compounds with 2,4-dichloro substitution on the phenyl ring and with a lower alkyl side chain on the dioxolane ring were found most promising for the control of powdery mildew on gherkins and barley, and for the control of bean rust. 

Asymmetric PTC is an important method in the synthesis of a-alkyl and a-amino acids. Belokon et al. [7] reported that the compound (47 ,57 )-2,2-dimethyl-Q ,Q ,Q , Q -tetra-phenyl-l,3-dioxolane-4,5-dimethanol (TADDOL) was used to catalyze the C-alkylation of C-H acids with alkyl halides to the asymmetric synthesis of a-methyl-substituted a-amino acids under PTC conditions. The alkylations of the substrate C-H acids with benzyl bromide or allyl bromide were conducted in dry toluene at ambient temperature with NaH or solid NaOH as base and TADDOL as a chiral promoter. The type of base is important in the asymmetric C-alkylation of C-H acids. 

Vinyl-functional alkylene carbonates can also be prepared from the corresponding epoxides in a manner similar to the commercial manufacture of ethylene and PCs via CO2 insertion. The most notable examples of this technology are the syntheses of 4-vinyl-1,3-dioxolan-2-one (vinyl ethylene carbonate, VEC) (5, Scheme 24) from 3,4-epoxy-1-butene or 4-phenyl-5-vinyl-l,3-dioxolan-2-one (6, Scheme 24) from analogous aromatic derivative l-phenyl-2-vinyl oxirane. Although the homopolymerization of both vinyl monomers produced polymers in relatively low yield, copolymerizations effectively provided cyclic carbonate-containing copolymers. It was found that VEC can be copolymerized with readily available vinyl monomers, such as styrene, alkyl acrylates and methacrylates, and vinyl esters.With the exception of styrene, the authors found that VEC will undergo free-radical solution or emulsion copolymerization to produce polymeric species with a pendant five-membered alkylene carbonate functionality that can be further cross-linked by reaction with amines. Polymerizations of 4-phenyl-5-vinyl-l,3-dioxolan-2-one also provided cyclic carbonate-containing copolymers. 

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