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1.
Jung JC Kache R Vines KK Zheng YS Bijoy P Valluri M Avery MA 《The Journal of organic chemistry》2004,69(26):9269-9284
A convergent, total synthesis of epothilones B (2) and D (4) is described. The key steps are Normant coupling to establish the desired (Z)-stereochemistry at C12-C13, Wadsworth-Emmons olefination of methyl ketone 28 with the phosphonate ester 8, diastereoselective aldol condensation of aldehyde 5 with the enolate of keto acid derivatives to form the C6-C7 bond, selective deprotection of acid 52, and macrolactonization. 相似文献
2.
Efficient syntheses of pheromone components of Aproaerema modicella starting from a common intermediate 7-octyn-1-ol is described. 相似文献
3.
A new protecting group for alcohols, the p-trimethylsilyl xylyl (TIX) group has been developed. The TIX group is used to protect various alcohols under acidic as well as basic conditions. The protected ethers thus formed had noteworthy chemoselectivity upon deprotection in the presence of other benzyl ethers and commonly used protecting groups. The stability of the TIX group towards various reagents has also been examined. 相似文献
4.
A practical synthesis of pheromone components of Achaea janata utilising double alkylations on TosMIC as key steps has been achieved. 相似文献
5.
The synthesis of novel N-acetyl-N,N-dipyrid-2-yl complexes of RhI and IrI, i.e. [RhCl(CH3CONPy2)(COD)] (1) and [IrCl(CH3CONPy2)(COD)] (2), respectively, is described. Upon prolonged treatment in CH2Cl2 at room temperature, complex 1 is transformed into a cationic Rh-complex, i.e. [Rh(CH3CONPy2)(COD)+RhCl2(COD)−] (1a). Compound 1a crystallizes in the monoclinic space group P21/c, complex 2 crystallizes in the triclinic space group . Compound 1 was investigated for its catalytic activity in the hydroformylation of cyclooctene as well as of 1-octene. In addition, 1 was used in various carbonyl hydrosilylation reactions of both aldehydes and ketones. There, turn-over numbers up to 50 000 and yields in the range of 85-100% were observed. Finally, compound 1 was successfully used for the polymerization of N2CHCOOEt yielding highly stereoregular poly(ethoxycarbonylcarbene) with Mw = 67 000 g/mol and a polydispersity index (PDI) of 2.59. 相似文献
6.
Lingaiah Nagarapu Hanmant K. Gaikwad Rajashaker Bantu Sheeba Rani Manikonda C. Ganesh Kumar Sujitha Pombala 《Tetrahedron letters》2012,53(10):1287-1291
A series of glycosidic-pyrroloquinolinone based novel building blocks of camptothecin (2a–g) were synthesized via Lewis acid-assisted olefin cross-metathesis reaction using Ti(OiPr)4 30 mol % and 10 mol % of Grubb’s second generation catalyst with good to excellent yields. Most of these compounds exhibited significant growth inhibitory effects on all the tested cancer cell lines and three compounds (2c, 2d and 2e) showed potent cytotoxic activity. 相似文献
7.
The synthesis of novel copper (I) N-heterocyclic carbene complexes is described. Thus, reaction of CuX with 1,3-di(2-propyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene yields CuX(1,3-di(2-propyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) (X=Cl, (1a), Br (1b)); however, reaction of CuCl with 1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene yields the bis-N-heterocylcic carbene complex Cu(1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene)2+CuBr2− (2). A supported version of 1, i.e. PS-DVB-CH2-OCO-CF2-CF2-CF2-COOCu(1,3-di(2-propyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) (3) was prepared from 1 and PS-DVB-CH2-OCO-CF2-CF2-CF2-COOAg. A copper loading of 4.15 μmol/g was realized. The new compounds were used as catalysts in carbonyl hydrosilylation and cyanosilylation reactions. Excellent reactivity was observed, giving raise to turn-over numbers (TONs) of up to 100,000. Compounds 1a, 1b, and 2 have also been used as catalysts for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). A linear conversion of monomer with time was observed, however, no control over molecular weight of PMMA was observed. 相似文献
8.
[reaction: see text] The combination of CrCl(2) and silyl chlorides converts aryl and conjugated aldehydes into olefinic adducts in good to excellent yields. When constrained by structural features, the intermediate vic-diol can be isolated. Available data are consistent with a novel chromium Brook rearrangement. 相似文献
9.
Lingaiah Nagarapu Gopal Paturi Satyender Apuri Rajashaker Bantu Renuka Bhavanthula 《合成通讯》2013,43(2):355-365
A simple and efficient procedure has been developed for one-pot synthesis of homoallylic alcohols and amines in good to excellent yields using a variety of aldehydes, amines, and allyltributylstannane in the presence of a catalytic amount of potassium dodecatungsto cobaltate trihydrate (K5CoW12O40 · 3H2O) as a heterogeneous catalyst at room temperature. The catalyst exhibited remarkable reusability. 相似文献
10.
BF3 mediated one-pot conversion of 3-O-acyl-d-glucose-1,2:5,6-diacetonide derivatives to 5-O-acyl-3,6-anhydro-d-glucose is described through a tandem selective intramolecular cyclization sequence. 相似文献