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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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Summary A novel synthesis of 8-methylisoquino[2,1-b][2,7]naphthyridinium salts7 is reported using the intramolecular cyclization of the 1-substituted isoquinolines5 as the key step, which in turn are obtained by alkylation of theReissert compounds1. The salts7 can be reduced by NaBH4 yielding the 8- and 8-methylstereomers (±)-alamaridine and (±)-epi-alamaridine9c and11c, respectively. 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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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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《Tetrahedron》1986,42(15):4297-4308
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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 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
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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》1987,28(21):2399-2402
2,3,9,10-Tetraoxygenated protoberberine alkaloids (14) were efficiently synthesized from the readily available benzaldehyde (2 or 10) via the benzylphenethylamines (11) and 2-phenethylisoquinolin-3-ones (12 and 13). 相似文献
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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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《中国化学快报》1997,(11)
Eversinceβ-vetivoneanditscongenerswererecognizedtohavespiro[4,5]decaneratherthanthehydroazuleneskeleton,[1]themembersofthisclasshavebecomeafavoritetargetforsynthesis.Herein.weshowafacileconversionofthemajorphotoproductformedinthereactionofmethyl2,4-dioxopentancate(1)with1,5-dimethyl-6-methylenecyclochexene(2)[2]intovetispiranederivatives,hinesol(3),ametaboliteofAtractylodeslancea[3,4],andagarospirol(4)foundinAquilariaagollocha,[5]inracemicforms,respectively.WhenanEtoAsolutionof1and2wasintema… 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