排序方式: 共有7条查询结果,搜索用时 0 毫秒
1
1.
M. I. Lazareva Yu. K. Kryschenko R. Caple W. A. Smit K. A. Lyssenko A. S. Shashkov 《Russian Chemical Bulletin》2000,49(1):85-97
The reaction of the bicyclic thiophanium ions salts, generated by the sequential interaction ofp-TolSCI with dihydropyran or 1-methoxycycloalkene and then with an acyclic alkyl vinyl ether in the presence of a Lewis acid
and with silicon- or tin-capped π-donors, proceeds with high diastereoselectivity at all newly created chiral centers.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 82–94, January, 2000. 相似文献
2.
Nguyen Quang VuDanielle Grée René GréeEric Brown Gilles Dujardin 《Tetrahedron letters》2003,44(34):6425-6428
Reaction of polysubstituted 2-hydroxyalkyldihydropyrans with DAST led regiospecifically to fluorination at the exocyclic position, except for primary alcohols. Difluorination of carbonylated analogues with deoxo-fluor™ occurred also regioselectively. The unexpected stability and synthetic potential of these new allylic fluorides are discussed. 相似文献
3.
M. I. Lazareva Yu. K. Kryschenko R. Caple W. A. Smit K. A. Lyssenko A. S. Shashkov 《Russian Chemical Bulletin》1990,49(1):85-97
The reaction of the bicyclic thiophanium ions salts, generated by the sequential interaction ofp-TolSCI with dihydropyran or 1-methoxycycloalkene and then with an acyclic alkyl vinyl ether in the presence of a Lewis acid
and with silicon- or tin-capped π-donors, proceeds with high diastereoselectivity at all newly created chiral centers.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 82–94, January, 2000. 相似文献
4.
Iodomethyl‐ and sulfonyl‐containing polysubstituted dihydropyrans were synthesized conveniently in high yield by FeCl3·6H2O catalyzed iodocyclization of allylic alcohols. 相似文献
5.
1,3,4,6-Tetramethyl-2,5-dioxabicyclo[2.2.2]octan-3,6-diol, which is the simplest analog of a natural bicyclic hemiketal, was
obtained and characterized.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 677–679, May, 2006. 相似文献
6.
Magdy Youssef Abdelaal 《Journal of polymer science. Part A, Polymer chemistry》2002,40(22):3909-3915
Polydi(3,4‐dihydro‐2H‐pyran‐2‐methyl) esters of oxalic, adipic, and phthalic acids were prepared at different temperatures in the presence of different cationic initiators, namely, the boron trifluoride/diethyl ether complex system, anhydrous ferric chloride, and p‐toluene sulfonic acid. The obtained polymers were hydrolyzed under basic conditions, and the polydispersity indices of these polymers were determined before and after hydrolysis. The results are discussed to shed some light on the ability to use this analysis to investigate the precise structure of the obtained polymers and to predict the ability of these polymers to form ladder or semiladder polymers. Characteristics of such polymers were dependent, to some extent, on the type of crosslinks and the cationic initiators used for polymerization as well as the reaction temperature. It seems possible to optimize the conditions leading to formation of ladder or semiladder polydi(3,4‐dihydro‐2H‐pyran‐2‐methyl) esters of oxalic acid and adipic acid, respectively. The ladder structure was confirmed through determination of the polydispersity index before and after hydrolysis of the polymer formed at different temperatures and through computer‐aided molecular modeling. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3909–3915, 2002 相似文献
7.
Trost BM Frontier AJ Thiel OR Yang H Dong G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(35):9762-9776
Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for the stereoselective assembly of the ring C subunit were developed. A Pd-catalyzed tandem alkyne-alkyne coupling/6-endo-dig cyclization sequence was explored and successfully pursued in the synthesis of a dihydropyran ring system. Elaboration of this methodology ultimately led to a concise synthesis of the ring C subunit of bryostatins. 相似文献
1