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1.
(+)-(1S,2S,5R)-8-联苯薄荷醇的合成 总被引:4,自引:0,他引:4
以(R)-( )-pu legone为起始原料,经1,4-加成,还原两步反应合成了手性辅助试剂( )-(1S,2S,5R)-8-联苯薄荷醇及其差向异构体(-)-(1R,2S,5R)-8-联苯薄荷醇,总产率95%。其结构经1H NMR,13C NMR,IR,MS和X-射线衍射仪表征。 相似文献
2.
Prashant K. Metri 《合成通讯》2020,50(9):1361-1366
AbstractFormal total synthesis of dihydrokawain-5-ol is accomplished starting from tartaric acid. Key reactions include Horner–Wadsworth–Emmons olefination, sodium borohydride mediated stereoselective reduction, orthogonal protection and deprotection of alcohols and ring closing metathesis. 相似文献
3.
Zahraa S. Al-Taie Barbara Bartholomew Christopher Cartmell Richard T. Froom Russell G. Kerr Rolf Kraehenbuehl Patrick J. Murphy Robert J. Nash Yana B. Penkova Alexander van Teijlingen 《Molecules (Basel, Switzerland)》2022,27(4)
The absolute stereochemistry of the marine alkaloid (+)-(R)-tiruchanduramine was established via a convergent total synthesis in six steps and 15.5% overall yield from Fmoc-D-Dab(Boc)-OH. 相似文献
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A strategy for the synthesis of optically active ring-A methoxylated indole alkaloids which employs the Moody azide/Schollkopf chiral auxiliary protocol has resulted in the successful preparation of 1-benzenesulfonyl-6-methoxy-D(+)-tryptophan ethyl ester 16. This amino ester is required for the synthesis of Alstonia bisindole alkaloids including macralstonine 2 via an enantiospecific Pictet-Spengler reaction. 相似文献
6.
Optically active (+)-(S)-5-sec-butyl- and (-)-(S)-3-sec-butyl-2(1H)-pyridinone are synthesized and the relationship between optical activity and minimum optical purity of the latter is determined. 相似文献
7.
《Tetrahedron: Asymmetry》1999,10(14):2739-2747
The synthesis of (+)-(R)-5-hydroxy-6-hydroxymethyl-7-methoxy-8-methylflavanone is described. A new chromylation method of β-ketosulfoxide 9 leading to the Michael acceptor 12 has been developed. Dilithium tetrachlorocuprate was shown to be a very efficient catalyst for the conjugate addition reaction of phenyl magnesium bromide to the α,β-unsaturated sulfoxide 12. The instability of the obtained adducts 10 represents a limitation in terms of yield. It was confirmed that the natural flavanone leridol does not possess the structure of title compound 1. 相似文献
8.
Two total syntheses of the potent protein kinase C inhibitory fungal metabolite balanol are described. In the first approach, the core aminohydroxyazepane subunit was prepared in racemic form by stereospecific functionalization of N-benzyl-epsilon-caprolactam. Resolution prior to coupling to the benzophenone subunit provided access to both enantiomers of balanol. In the second approach, an efficient silicon-mediated cyclization of (2S,3R)-3-hydroxylysine followed by reduction provided the azepane subunit in enantiomerically pure form. The sterically congested benzophenone subunit was assembled from two highly substituted aromatic precursors by way of an anionic homo-Fries rearrangement. 相似文献
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The enantiospecific synthesis of (-)-trachyspic acid () is presented. This has allowed for the assignment of the absolute configuration of natural (+)-trachyspic acid as 3S,4S,6S. 相似文献
12.
Francesco G. Gatti 《Tetrahedron letters》2008,49(34):4997-4998
The sesquiterpene (+)-hernandulcin has been enantiospecifically synthesized starting from (−)-neoisopulegol in seven steps and in 25% overall yield. 相似文献
13.
Donohoe TJ Cheeseman MD O'Riordan TJ Kershaw JA 《Organic & biomolecular chemistry》2008,6(21):3896-3898
The partial reduction of electron deficient pyrroles is an extremely versatile method that allows us to prepare substituted pyrrolidines and pyrrolizidines with trans-diol stereochemistry on the five membered ring. 相似文献
14.
Enantiospecific synthesis of the natural enantiomer of the marine sesquiterpene (-)-4-thiocyanatoneopupukeanane (6) is described. The bicyclo[2.2.2]octanecarboxylate 14, obtained from (R)-carvone via Michael-Michael reaction, was transformed into neopupukeananedione 12 by employing rhodium acetate catalyzed intramolecular C-H insertion of the diazo ketones 16 or 19 as the key reaction. Regioselective deoxygenation of the C-2 ketone transformed the dione 12 into neopupukean-4-one 10. Alternately, the keto ester 18 was also transformed into neopupukean-4-one 10 via regioselective deoxygenation of the ketone in 18 followed by intramolecular rhodium carbenoid C-H insertion of the diazo ketone 31. Finally, neopupukean-4-one 10 was transformed into (-)-4-thiocyanatoneopupukeanane 6 via the alcohol 32 and the mesylate 33. 相似文献
15.
Enantiospecific total synthesis of the crinipellin mentioned in the title was accomplished. In the present synthesis cyclopentane ring in campholenaldehyde was identified as the B-ring, two intramolecular rhodium carbenoid CH insertion reactions were employed for the construction of the A and C rings, and an intramolecular Michael addition reaction was utilized for the construction of the D-ring of crinipellin. 相似文献
16.
Total synthesis of (3R, 5R)-(+)-3-hydroxy-5-decanolide (1) and massoialactone (2), and formal synthesis of verbalactone (3), have been reported. 相似文献
17.
《Tetrahedron: Asymmetry》1998,9(2):189-191
Enantiopure (2R,5R)-(+)-2,5-dimethylthiolane was synthesized by cyclization with sodium sulfide of the dimesylate of (2S,5S)-(+)-2,5-hexanediol, which was obtained by baker's yeast (Saccharomyces cerevisiae) reduction of acetonyl acetone in high enantiomeric purity. The structure of the diol and absolute stereochemistry of the sulfone derived from the title molecule were determined by X-ray crystal structure analysis. 相似文献
18.
A biomimetic synthesis of the triterpene (±)-perovskone was achieved featuring a remarkable polycyclization process in which three rings, four bonds, and five stereocenters were created in a single operation in 82% yield. This convergent synthesis required 16 steps, starting from vanillin, and proceeded in 9% overall yield. A second route to prepare optically active quinone 2 took 15 steps in 36% overall yield and featured a palladium-catalyzed reductive allylic transposition to establish the C-5 chirality stereospecifically. Quinone (−)-2 was converted to (+)-perovskone (1) via a polycyclization cascade, which created four rings, five bonds, and six stereocenters in a single operation in 50% yield. 相似文献
19.
G. Chelucci M. Marchetti F. Soccolini C. Botteghi 《Journal of heterocyclic chemistry》1984,21(6):1717-1719
Optically active (S)-5-s-butyl-2(1H)-pyridinone ( 6 ) is obtained by reaction of 2-s-butylacrolein ( 1 ) and N-(carbamylmethyl)pyridinium chloride. The relationship between optical activity and minimum optical purity is determined. 相似文献
20.
The synthesis of racemic 8-fluorogalanthamine and its separation into (−)- and (+)-8-fluorogalanthamine (= (4aS,6R,8aS)- and (4aR,6S,8aR)-1-fluoro-4a,5,9,10,11,12-hexahydro-3-methoxy-11-methyl-6H-benzofuro[3a,3,2-ef][2]benzazepin-6-ol) is described. 相似文献