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1.
A concise synthesis of (±)-cylindricine C and its C(13)-epimer is described. Starting from 1-octyne, cylindricine C and 13-epi-cylindricine C were prepared in 11% and 15% yields, respectively. The synthesis involves the preparation of the central tricyclic moiety via a radical α-iodoketone carboazidation/bis-reductive amination sequence. Inversion of the stereochemistry at C(13) and C(5) was efficiently achieved on late stage intermediates. 相似文献
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The syntheses of (±)-curcuphenol 1, (±)-curcudiol 2, (±)-curcuhydroquinone 3, and (±)-curcuquinone 4 have been achieved. The key steps involved in the syntheses were the Reformatsky reaction and hydrogenation reaction. 相似文献
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Aporphines, (±)-thaliporphine (1). (±)-N-methyllaurotetatine (2), and (±)-isoboldine (3) were synthesised using photochemical cyclization as the key step. 相似文献
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A full account of the total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine is presented. Two approaches have been developed to construct the basic pyrrolo[1,2-a]azepine core of the Stemona alkaloids, featuring a tandem semipinacol/Schmidt rearrangement of a secondary azide and a highly stereoselectively desymmetrizing intramolecular Schmidt reaction, respectively. To build the common spiro-γ-butyrolactone, a new protocol was carried out by utilizing an intramolecular ketone-ester condensation as the key transformation. The vicinal butyrolactone moiety of (±)-maistemonine was stereoselectively introduced via a one-pot procedure involving the epimerization at C-3 and carbonyl allylation/lactonization. Moreover, (±)-stemonamide was divergently synthesized from a common intermediate, and (±)-isomaistemonine was obtained via the epimerization of (±)-maistemonine at C-12. 相似文献
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XS Xu ZW Li YJ Zhang XS Peng HN Wong 《Chemical communications (Cambridge, England)》2012,48(68):8517-8519
The first total synthesis of (±)-pallambins C and D has been accomplished in a linear 38 step reaction from (±)-Wieland-Miescher ketone. The key conversions are featured as follows: a Grob fragmentation-intramolecular aldol cyclization and a thiourea/palladium-catalyzed carbonylative annulation. 相似文献
6.
The first total synthesis of (±)-subincanadine C has been accomplished in a protecting-group-free fashion. This pentacyclic indole alkaloid was synthesized in six steps from the known intermediate 4, featuring Ni(COD)(2)-mediated intramolecular Michael addition as a key transformation. 相似文献
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Photochemical cyclization of 3 afforded 5, 4 and 8.5 on LAH reduction furnished (±)-glaucine (6) and on treatment with ethanolic HCl afforded (±)-norglaucine (7). 10 obtained by the photocyclization of 9 was converted into 7 and 11 via 12. 相似文献
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A total synthesis of (±)-boschnialactone ( 1 ) and (±)-tertahydroanhydrodesoxyaucubigenin ( 2 ) is described and trisubstitued cyclopentenoid 3 is a key intermediate. 相似文献
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《Tetrahedron letters》1988,29(43):5525-5528
Dispiro[3.0.4.2] undecane 1 has been synthesized and rearranged to (±)modhephene 2 and triquinane 3 under kinetic control, and to (±)isocomene 4 and triquinane 5 under thermodynamic control. Molecular mechanics calculations (MM2) support the mechanism proposed. 相似文献
11.
Chen ZH Zhang YQ Chen ZM Tu YQ Zhang FM 《Chemical communications (Cambridge, England)》2011,47(6):1836-1838
The first total synthesis of polycyclic Stemona alkaloid maistemonine has been achieved. The efficient approach features a stereoselective intramolecular Schmidt reaction, a ketone-ester condensation, and a Reformatsky reaction. Additionally, another Stemona alkaloid stemonamide was divergently synthesized from a common intermediate. 相似文献
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《Tetrahedron》1986,42(15):4297-4308
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Annulation: The efficient synthesis of 3-hydroxyalkyl isoquinolones and 6-hydroxyalkyl 2-pyridones is enabled through the intramolecular annulation of alkyne-tethered hydroxamic esters (see scheme, Cp*=pentamethylcyclopentadienyl). The reaction features high regioselectivity, broad substrate scope, and excellent functional-group tolerance, proceeds under mild reaction conditions with low catalyst loading, and obviates the need for an external oxidant. 相似文献
16.
Total syntheses of (±)-securinine and (±)-allosecurinine that employ a tandem rhodium carbenoid-initiated Claisen/α-ketol rearrangement sequence as a key step are described. 相似文献
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《合成化学》2015,(6)
以取代苯乙酮和5-醛基-8-甲氧甲氧基-2-甲基-2-(4'-甲基-3'-戊烯基)-二氢-1-苯并吡喃为原料,经羟醛缩合反应制得两个中间体——7,2',4'-三甲氧甲氧基-6'-羟基-2-甲基-2-(4'-甲基-3'-戊烯基)-二氢-1-苯并吡喃查尔酮(3a)和7,2',4'-三甲氧甲氧基-5'-异戊烯基-6'-羟基-2-甲基-2-(4'-甲基-3'-戊烯基)-二氢-1-苯并吡喃查尔酮(3b);3a经环合和脱保护基反应合成了(±)-Malaysianone A(4a),产率12.9%;3b经脱保护基和环合反应合成了(±)-Tanariflavanones B(4b),产率5.2%。4a和4b的结构经1H NMR,13C NMR和HR-ESI-MS确证。 相似文献