Bis-cyclic carbonate

Condensation of 911 with ketophosphonate 913, prepared in 92% yield from 912, provides enone 914 in 88% yield. Subsequent functional group transformation converts 914 to the labile bis-cyclic carbonate 915. Treatment of 915 with a large excess of dimethyl sulfide in the presence of benzoyl peroxide followed by basic hydrolysis provides the tetraol 916. When 916 is treated with trimethylorthoacetate in the presence of catalytic PPTS followed by tri-methylsilyl chloride in a triethylamine buffer, the exclusive product is the diacetoxy dichloride 917. Base-mediated saponification of cmde 917 results in spontaneous cyclization to the bis-trans-QpoxidQ, which after treatment with a large excess of mercury(II) chloride affords (— )-depudicin (918) in 52% yield. The total synthesis involves 22 steps, and provides 918 in 1.4% overall yield [255] (Scheme 198). 

Scheme 4.29 Synthesis of bis-cyclic carbonate macromonomers based on methyl 10-undecenoate. TBD l,5,7-Triazabicyclo[4.4.0]dec-5-ene and UndBdA undecenylbisdiamide [128]...

An example of its exploitation by more conventional mechanisms relates to the synthesis of bis-cyclic carbonates [129]. Methyl 10-undecenoate was reacted with various diols and diamines to open the pathway to the synthesis of the corresponding bis-carbonates macromonomers bearing an ester or an amide core, as shown in Scheme 4.29 for the case of butane-l,4-diamine. These reactive intermediates were then used to prepare polyhydroxyurethanes (PHU) using a wide selection of diamines following the coupling reactions shown in Scheme 4.30. 

Nonisocyanate hybrid coatings were studied using a phosphine oxide-based bis(cyclic carbonate) prepared in three steps starting from bis(4-hydro>yphenyl)phenylphosphine oxide and epichlorohydrin as shown in Scheme 63. ... 

The best procedure for obtaining a cyclic carbonic ester requires that CDI (4 equiv.) be added gradually over a period of ca. eight hours during refluxing of the reaction mixture. However, it was found in the case of cw-cyclohexane diol that if the diol and CDI are dissolved together in benzene and the solution heated under reflux, the bis(imidazole-iV-carboxylate) is obtained instead of the cyclic carbonic ester. 4 ... 

Just as certain pyranose sugars can give rise to bis-acetal or bis-ketal derivatives which constitute linearly fused 5 6 6 systems (cf. Section 12.17.2.1.7), another set of bis-acetals and bis-ketals - in many cases derived from the same sugars - correspond to angularly fused 5 6 6 systems. These, like their linearly fused analogues, serve to protect, selectively, four hydroxyl groups of the parent sugars, and cyclic carbonates (l,3-dioxolan-2-ones) may fulfill similar functions. 

Cyclic aromatic disulfides, polymerization reactions of, 23 706 Cyclic (arylene) disulfides, 23 712 Cyclic batch adsorption processes, 1-613 Cyclic bis(arylene tetrasulfide)s, 23 712 Cyclic carbon, polymer materials with, 15 177... 

The formation of the adduct between 86 and the nitrile, i.e., 89, occurs more readily than that between 86 and ketones, since an activated nitrile is a better nucleophile than a ketone. Since the ce-proton in the adduct 89 is more acidic than the ce-proton in the ketonic adduct, also the ring opening will occur more easily. The interchange of a nitrile carbon with the ring carbon of a pyrimidine ring was also observed with the 3-benzyloxymethyl-l-ribosyl-5-cyanouracil. With a series of activated nitriles, the protected bi-cyclic nucleosides are formed. After deprotection, the corresponding bi-cyclic nucleosides are obtained (Scheme IV.35). 

Due to its high ionic character, the carbon-lithium bond is very reactive and adds under mild conditions to ethylene or dienes and under more severe conditions to other alkenes. Some functionalized alkenes can be used, and high regio- and stereo-selectivity is usually observed in these carbolithiation reactions, especially if a precoordination of the lithium organometallic with the alkene is possible. Intramolecular carbolithiations of alkenes proceed under mild conditions and allow the preparation of several stereochemically well defined mono- and bi-cyclic compounds. Alkynes are too reactive, and can lead, with organolithium derivatives, to several side reactions, and seldom afford the desired carbolithiated product in good yield. 

Ethylene reacted with iodonium salts in the presence of a palladium catalyst and a base to afford directly 1,2-bis arylated products (stilbenes). Styrene underwent arylation under similar conditions [44], Allylic cyclic carbonates were efficiently phenylated by diphenyliodonium tetrafluoroborate because of the mild conditions, no ring opening occurred, as was the case when iodobenzene was used. 

Terminal epoxides react with DMF in the presence of BiBr3 under an 02 atmosphere to afford cyclic carbonates (Equation (87)).143 Para-quinones react with acetic anhydride under the catalysis of Bi(OTf)3 to give acetoxy-1,4-hydroquinone diacetates (Equation (88)).144... 

Russian workers have demonstrated that cyclooctane can be dehydrogenated to crs-bicyclo[3.3.0]octane when passed in the gas phase over a heated catalyst such as platinum on carbon, platinum and iron on carbon, or nickel on Kieselguhr.93-98 Unfortunately, the yields are highly variable (0.5—70 %) and details of these processes are scanty. Perhaps more promising is their discovery that n-octane and its cyclodehydrogenation product n-propylcyclopentane can be converted to the bi-cyclic hydrocarbon under comparable conditions. 

Korshin et al. reported an outstanding double stereoselective alkenyla-tion through a 1,5 sulfur-to-carbon translocation on a proline-derived scaffold [169]. 5-Exo-trig cyclization of the radical derived from 181 led to bi-cyclic adduct 182, which collapsed to the open thiyl radical (Scheme 59). The sole stereocontrol exerted by the cyclization step allows for the resulting vinyl translocation to occur entirely stereoselectively. Since the reaction was carried out in the presence of a styryltin derivative, consecutive intermolecular vinylation occurred, leading to bisvinyl compoimd 183 in very high yield (86%). The styrylsulfonyl moiety could be converted to a formyl group. 

Polymerizations via the hydroxyl group of 3,3-bis(hydroxymethyl) thietane have been used to prepare polyurethanes " and polyethers. " Tin derivatives are stabilizers for poly(vinyl chloride) as well as being used in polyurethane formation. Cyclic carbonate derivatives are homo- or copolymerized to high-molecular-weight solids. The methacrylate ester of 3-hydroxythietane has been copolymerized with methyl methacrylate. ... 

Thietane 1-oxide may absorb carcinogens.The cyclic carbonate derived from bis(3,3-hydroxymethyl)thietane 1-oxide can be homo- or copolymerized to give high-molecular-weight solids.The sulfoxide of compound 52 is said to be useful in the preparation of pesticides, pharmaceuticals, and high-melting plastics. 3-aryloxythietane 1-oxides are claimed to be useful as herbicides, fungicides, insecticides, acaricides, antioxidants, stabilizers for plasticizers, and dye intermediates. Quinazoline derivatives of thietane 1-oxide carboxylic acids may be antihypertensive. 

Addition of hydrogen sulfide (0.5 molar equivalent) to cyclopropanone in dichloromethane afforded the bis-adduct 1, which could be spirocyclized with excess phosgene in the presence of pyridine to give 8,10-dioxa-4-thiadispiro[2.1.2.3]decan-9-one (2). Thermolysis of this cyclic carbonate at 495°C in vacuo (0.5 Torr) yielded methylenethiirane 3, an elusive species in the methyleneheteracyclopropane series. 

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