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Suttipol Radomkit Pakornwit Sarnpitak Jumreang TummatornParatchata Batsomboon Somsak RuchirawatPoonsakdi Ploypradith 《Tetrahedron》2011,67(21):3904-3914
Novel intermolecular and intramolecular generations of ortho-quinone methides and their formal [4+2]-cycloaddition reactions with olefins catalyzed by PtCl4 and AuCl3 under mild conditions have been developed. Good to excellent yields (up to 99%) and diastereoselectivity (up to >99:1) of the chromans were obtained. PtCl4 was found to be effective and compatible with various functional groups present in the substrates. A mechanism accounting for its catalytic cycle is proposed and discussed. 相似文献
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Inside Back Cover: Facile and Divergent Synthesis of Lamellarins and Lactam‐Containing Derivatives with Improved Drug Likeness and Biological Activities (Chem. Asian J. 12/2015) 下载免费PDF全文
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Total synthesis of natural and unnatural lamellarins with saturated and unsaturated D-rings 总被引:1,自引:0,他引:1
Ploypradith P Petchmanee T Sahakitpichan P Litvinas ND Ruchirawat S 《The Journal of organic chemistry》2006,71(25):9440-9448
Twenty-eight natural and unnatural lamellarins with either a saturated or an unsaturated D-ring were synthesized according to our developed synthetic route. The key step involved the Michael addition/ring closure (Mi-RC) of the benzyldihydroisoquinoline and alpha-nitrocinnamate derivatives, which provided the 2-carboethoxypyrrole intermediates in moderate to good yields (up to 78% yield). Subsequent hydrogenolysis/lactonization furnished lamellarins with a saturated D-ring in excellent yields (up to 93% yield). DDQ oxidation of the saturated lamellarin acetates led directly to the corresponding unsaturated analogues in 54-95% yield. In addition, only two steps in our developed strategy require column chromatography. 相似文献
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Selective deprotection of aromatic ethers bearing two protecting groups on the same aromatic ring by solid-supported acids (Amberlyst-15 and PTS-Si) was systematically investigated. ortho-Directing protonation by the carbonyl group as well as carbocation stability and quenching are the important determining factors for the orthogonal deprotection process. Stablilized carbocations (e.g., those from the MOM and PMB groups) could be removed with high selectivity. 相似文献
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Worayuthakarn R Boonya-udtayan S Arom-oon E Ploypradith P Ruchirawat S Thasana N 《The Journal of organic chemistry》2008,73(18):7432-7435
A synthesis of unsymmetrical 1,2-diarylethane-1,2-dione is reported involving the intramolecular cyclization of anionic benzylic ester of the aryl benzyl ether followed by oxidation employing dioxirane. With the use of microwave irradiation, licoagrodione was prepared from Claisen rearrangement of the corresponding allyl phenyl ether 1,2-diketone readily available from the Lindlar's reduction of the corresponding alkyne derivative. Subsequent removal of protecting groups then furnished the desired product. 相似文献
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Six-membered ring cyclisation of N-ethylbenzazepinone, prepared from the condensation of benzazepinone with phenethyl iodide under basic conditions, smoothly provided the corresponding product, isoquino[1,2-b][3]benzazepinone, under acid-mediated conditions. On the other hand, the attempted direct five-membered ring cyclisation using the acid-mediated conditions failed to give the 7,5 fused ring isoindolinobenzazepinone from N-benzylbenzazepinone, but the 7,6 fused ring product was instead obtained. However, five-membered ring cyclisation of N-benzylbenzazepinone could be effected efficiently by employing the Heck reaction followed by catalytic hydrogenation to furnish the desired isoindolinobenzazepinone. 相似文献
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Starting from two commercially available phenol derivatives, the thyroid hormone analog, GC-1, was successfully prepared. The strategy featured a convergent coupling of the two halves via the Lewis/Brønsted acid-mediated regioselective Friedel–Crafts-type (FC-type) benzylation to furnish the corresponding diarylmethane core as the key step. Various transition metal triflates were screened as catalysts for this key step, among which Bi(OTf)3 was found to be the most effective. 相似文献