Allyl ethyl carbonate

Enantioselectivity (which is hnked to the regioselectivity of the attack of the nucleophile to the coordinated allyl) in the allylic amination of 1,3-diphenyl-allyl ethyl carbonate was also very low compared to the P-N system. This was attributed to the comparable fran -influence of P and NHC functionalities, leading to poor regioselec-tion of the two aUyl termini trans to the P and NHC ligands by the nucleophile [95],... 

Generation and Reaction of Allyltitanium Reagents (Section 9.3) 2-(4-Bromophenyl)-l-phenyl-3-buten-l-ol [42] To a solution of l-(4-bromophenyl)allyl ethyl carbonate (285 mg, 1.0 mmol) and Ti(OiPr)4 (0.296 mL, 1.0 mmol) in diethyl ether (5 mL) was added iPrMgBr (1.20 m in diethyl ether, 2.0 mmol) at 50 °C. The resulting yellow solution was stirred at —50 to —40 °C for 1.5 h, in the course of which it became brown. Benzaldehyde (74.3 mg, 0.70 mmol) was then added at —40 °C and the mixture was allowed to warm to 0 °C over a period of 30 min. After the addition of aqueous 1 n HC1 (5 mL) at this temperature, the mixture was allowed to warm to ambient temperature. The organic layer was separated and the aqueous layer was extracted with diethyl ether (10 mL). The combined organic layers were washed with saturated aqueous NaHC03 solution (5 mL), dried over... 

An example of a neutral, chemoselective palladium-catalyzed carbon-allylation is the reaction of allyl ethyl carbonate with one equivalent of the nitroacetic ester shown below. 

Allylic substitutions. Both carbon and nitrogen nucleophiles are suitable for displacement of allylic substrates. Thus, A -allylation of TV-protected amino acid esters and peptides is readily performed at room temperature under neutral conditions with allyl ethyl carbonate. Regiocontrol of alkylation by addition of Lil is noted. Heteroatom-directed regioselective substitution is observed. ... 

This ratio may also be estimated from a deteimination of the amount of initiator residues found in the monomer. From such data the significance of degradative chain-transfer in an allyl ester polymerization can be judged. For example, it was found that in the allyl ethyl carbonate polymerization, degradative chain-transfer predominates, whereas in the polymerization of allyl laurate and allyl benzoate, effective chain-transfer predominates [19]. 

The order of decreasing degradative chain-transfer constants for a series of allyl esters has been given as allyl ethyl carbonate > allyl acetate > allyl propionate > allyl laurate > allyl trimethylacetate [20]. 

Besides VC, vinyl ethylene carbonate (VEC), phenylethylene carbonate (PhEC), ° phenylvinylene carbonate (PhVC), catechol carbonate (CC), - ally methyl carbonate (AMC), - allyl ethyl carbonate (AEC), vinyl acetate (VA), and other vinyl compounds, - - acryronitrile (AAN) - and 2-cyanofuran (CN-F), whose chemical structures are given in Fig. 4.10, showed the similar effect and no graphite exfoliation in PC solvent systems. 

Homoallylic nitro compounds 845 are accessible by conversion of allylic alcohols to carbonates followed by their palladium-catalyzed solvolysis in nitromethane [618]. Ethoxycarbonylation of the alcohols 843 with ethyl chloroformate provides the corresponding allylic ethyl carbonates in high yields (99% in the case of 844). Exposure of these substrates to catalytic palladium(O) in nitromethane initiates a reaction sequence of ionization - decarboxylation - nitromethylation, which culminates in the formation of nitroalkenes 845. 

A convenient preparation of 2 -0-methylguanosine involves the interaction of N -isobutyiyl-5 -0-dimethoxytritylguanosine with trimethylsilyldiazomethane, followed by deprotection.279 Allylation of uridine and cytidine at 0-2 can be achieved with some regioselectivity by use of either allyl ethyl carbonate and a Pd° catalyst, in which case protection of A3- of the uracil unit was necessary,280 or by allylation of a stannylene derivative.28i Alkylation of UMP also has some selectivity towards 0-2. 282... 

Other Alkyl and Aryl Ethers. - The reagent system of allyl ethyl carbonate and a Pd(0) catalyst, applied to carbohydrate alcohols, has been utilised for making allyl ethers under neutral conditions. The synthesis of benzyl ethers from the parent alcohols under non-basic conditions has been achieved using phenyldiazomethane and HBF4. Dibutylstannylene compounds derived from benzyl -D-lactoside and its derivatives have been regioselectively benzylated. ° Similarly, 2,2 -di-0-alkyl-4,6 4 6 -di-0-benzylidene-Qt,a-trehaloses have been prepared by regioselective alkylation of a dibutylstannylene derivative. Phase transfer catalysed benzylation... 

Prepare allyl ethyl carbonate, required for the allylation reactions, according to the detailed published procedure (75 Prepare the condensing agent 5-(4-nitrophenyl)-lH-tetrazole as previously described (75). Synthesize 3, 5 -0-(tetraisopropyldisiloxane-1,3-diyl)-6-(2,6-dichlorophe-noxy)purine riboside and 3, 5 -0-(tetraisopropyldisiloxane-l,3-diyl)-2-chloro-6-(2,6-dichlorophenoxy)purine riboside, required as starting materials for the synthesis of the 2 -0-allyl A and G monomers, respectively, according to the detailed published procedures (15). 

Fig. 1 Reaction scheme for the synthesis of the 2 -0-allyluridine building block Reagents i, l,3-dichlorO l,l,3,3-tetraisopropyldisiloxane in pyridine ii, chlorotri-methylsilane, and triethylamine in 1,2-dichloroethane, iii, 2-mesitylenesulfonyl chloride, triethylamine, and 4-dimethyIaminopyndine in dichloromethane iv, 2,6-dichlorophenol, l,4-diazabicyclo[2 2.2]octane and triethylamine v, p-toluene sulfonic acid monohydrate in THF/dichloromethane, vi, allyl ethyl carbonate, l,4-bis(diphenylphosphino)butane and tris(dibenzylideneacetone)dipalladium(0) in tetrahydrofuran, vii, tetrabutylammonium fluoride in tetrahydrofuran viii, 2-nitro-benzaldoxime and 1,1,3,3-tetramethylguanidine in acetonitrile, ix, 4,4 -dimethoxytrityl chloride and triethylamine in pyridine x, 2-cyanoethoxy M -diisopropyl-aminochlorophosphine and //,iV-diisopropylethyiamine in 1,2-dichloroethane.

Lakhmiri, R, Lhoste, P., and Sinou, D. (1989) Allyl ethyl carbonate/palladium (0), a new system for the one step conversion of alcohols into allyl ethers under neutral conditions Tetrahedron Lett 30,4669-4672. 

Lee JT, Lin YW, Jan YS (2004) Allyl ethyl carbonate as an additive for lithium-ion battery electrolytes. J Power Sourc 132 244—248... 

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