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An efficient enantioselective cascade sulfa‐Michael/Michael addition reaction of trans‐3‐(2‐mercaptophenyl)‐2‐propenoic acid ethyl ester with nitroalkenes catalyzed by a chiral squaramide catalyst was disclosed. This cascade reaction afforded thiochroman derivatives with three contiguous stereocenters in high yields (up to 94%), excellent diastereoselectivities (up to >25:1 dr) and enantioselectivities (up to 99% ee). 相似文献
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Jacek Skar?ewski Mariola Zielińska-B?ajetSzczepan Roszak Ilona Turowska-Tyrk 《Tetrahedron》2003,59(20):3621-3626
Optically active (3R,1RS)-3-aryl-1-phenyl-3-phenylsulfanyl-1-propanols were easily dehydrated forming mainly rac-cis-2-aryl-4-phenylthiochroman, and rac-cis-4-aryl-2-phenylthiochroman along with the corresponding trans-isomers. The observed reaction outcome (rearrangement and racemisation) apparently results from the SEAr reaction involving the unusual 1,3-phenylsulfanyl group migration. This interpretation is supported by the results of theoretical studies (DFT) on the supposed intermediates. 相似文献
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《中国化学》2018,36(10):921-924
A C—H sulfurated cyclization protocol starting from thioacetates is developed for straightforward construction of sulfur‐containing benzoheterocyclics. The diversiform functional dihydrobenzothiophenes and thiochromans were comprehensively achieved through the Pd‐catalyzed carbon‐ sulfur cyclization. Mechanistic studies indicated that C—H bond cleavage was involved in the rate‐determining step. [1]Benzothieno‐[3,2‐b]‐ [1]benzothiophene (BTBT) and benzo[b]thieno[2,3‐d]thiophene (BTT) were efficiently established as the well‐known organic field‐effect transistor (OFET) material molecules through this methodology. 相似文献
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Katritzky AR Akhmedov NG Wang M Rostek CJ Steel PJ 《Magnetic resonance in chemistry : MRC》2004,42(12):999-1011
Regioselective addition of allylthiol at the C-3 position adjacent to the nitrogen carrying the phenyl group of the 1,4-phenylenediamine moiety of compounds 1-4 was rigorously confirmed by 1D NOE difference in combination with gHMBC experiments. The structures of 1,4-phenylenediamines 1-4, allylsulfanyl-N1-alkyl-N4-phenyl-1,4-phenylenediamines 5-8 and cyclization products 9-14 were completely analyzed in both CDCl3 and DMSO-d6 solutions. The 1H and 13C NMR spectra of 10 and 11, which contain two chiral centers, exhibit duplication for several signals, indicating the existence of two diastereomeric forms. The full structures of 5 and 9 were unambiguously confirmed by x-ray crystallography. The 1H and 13C NMR spectra of all compounds were assigned using one- and two-dimensional NMR techniques (APT, DEPT, 1D NOE difference, COSY, NOESY, HETCOR, gHMQC and gHMBC). 相似文献
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