(±)-Diplacone与(±)-3'-O-methyldiplacone的全合成

以廉价的香草醛,3,4-二羟基苯甲醛和2,4,6-三羟基苯乙酮为初始原料,经过C-香叶基化、羟基保护、羟醛缩合、脱去保护基以及催化环化等步骤,以11%和20%的总收率实现了两个天然香叶基黄烷酮(±)-diplacone与(±)-3′-O-methyldiplaone的首次全合成,其结构经¹H NMR, IR和MS表征。     

Total syntheses of (±)-securinine and (±)- allosecurinine

Total syntheses of (±)-securinine and (±)-allosecurinine that employ a tandem rhodium carbenoid-initiated Claisen/α-ketol rearrangement sequence as a key step are described.     

Total synthesis of (±)-cycloclavine and (±)-5-epi-cycloclavine

Novel routes to the naturally occurring indole alkaloid cycloclavine and its unnatural C(5)-epimer are described. Key features include the rapid construction of the heterocyclic core segments by two Diels-Alder reactions. An indole annulation was accomplished by a late-stage intramolecular Diels-Alder furan cycloaddition, and a methylenecyclopropane dienophile was used for a stereoselective intramolecular [4 + 2] cycloaddition to give the cyclopropa[c]indoline building block present in cycloclavine.     

(±)-Galbulin和(±)-8,8′-epi-aristoligone的全合成

(±)-galbulin和(±)-8,8′-epi-aristoligone属于苯代四氢萘型木脂素类化合物,具有广泛的生物活性.以3,4-二甲氧基苯乙酸为起始原料,采用Horner-Wadsworth-Emmons反应和Friedel-Crafts反应为关键步骤,经8步得到了(±)-galbulin,并通过将(±)-galbulin苄位氧化得到(±)-8,8′-epi-aristoligone.该法操作简单,路线较短,为苯代四氢萘型木脂素化合物的合成提供了参考.     

(±)-亮氨酸的合成

以氨基丙二酸二乙酯盐酸盐(2)为原料通过一条全新路线合成了外消旋亮氨酸盐酸盐(1)。2的氨基经Boc保护制得Boc-氨基丙二酸二乙酯(3);3与甲代烯丙基氯发生取代反应制得Boc-氨基-(2-甲基-2-丙烯基)丙二酸二乙酯(4);4经Pd/C催化加氢制得Boc-氨基-(2-异丁基)丙二酸二乙酯(5);5在浓盐酸中回流反应,一步完成脱保护、脱羧、水解过程合成1。总收率55%,其结构经1H NMR和MS确证。     

First total synthesis of (±)-puyanin and (±)-4'-O-methylbonannione

<正>A facile approach for the first total synthesis of two naturally occurring geranylated flavonoids,(±)-puyanin 1 and(±)-4'-O- methylbonannione 2 has been obtained with total yield 27%and 21%,respectively.The key steps were regioselective cyclization of geranylated trihydroxychalcone and regioselective geranylation of 2,4,6-trihydroxyacetophenone.     

First Total Synthesis of(±)-Puyanin and(±)-4'-Omethylbonannione

A facile approach for the first total synthesis of two naturally occurring geranylated flavonoids, (±)‐puyanin ( 1 ) and (±)‐4′‐O‐methylbonannione ( 2 ) has been obtained with total yields of 27% and 17.8%, respectively. The key steps were regioselective cyclization of geranylated trihydroxychalcone and regioselective geranylation of 2,4,6‐trihydroxyacetophenone.     

Facile Syntheses of (±)-Curcuphenol, (±)-Curcudiol, (±)-Curcuhydroquinone,and (±)-Curcuquinone

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.     

螺环倍半萜(±)-α-花柏烯和(±)-β-花柏烯的全合成

以萜品油烯(terpinolene)与2,4-二氧代戊酸甲酯的deMayo反应得到的加成产物为起始原料,经反-aldol重排,再环合成具有螺[5.5]十一烷结构的基本碳架,通过官能团的化学修饰,完成了(±)-α-花柏烯和(±)-β-花柏烯的全合成。     

螺环倍半萜(±)-α-花柏烯和(±)-β-花柏烯的全合成

以萜品油烯 ( terpinolene)与 2 ,4 -二氧代戊酸甲酯的 de Mayo反应得到加成产物为起始原料 ,经反 aldol重排 ,再环合成具有螺 [5 ,5 ]十一烷结构的基本碳骨架 ,通过官能团的化学修饰 ,完成了 (± ) -α-花柏烯和 (± ) -β-花柏烯的全合成     

(±)-迷迭香酸(Rosmarinic acid)的全合成

以藜芦醛为起始原料,经Erlenmeyer反应、水解开环、还原、羧基保护、酯化缩合、Kunz-Waldmann转化、脱甲基7步反应,完成了(±)-迷迭香酸(Rosmarinic acid)的全合成,并重点对甲醚化迷迭香酸脱甲醚方法进行了研究,探索出一条原料便宜易得、高收率的(±)-迷迭香酸合成路线.     

Photochemical Symthesisof Aporphines: (±)-Thaliporphime. (±)-N-Nethyllaurotetanineand(±)-Isoboldime

Aporphines, (±)-thaliporphine (1). (±)-N-methyllaurotetatine (2), and (±)-isoboldine (3) were synthesised using photochemical cyclization as the key step.     

Synthesis of (±)-7-hydroxylycopodine

A six step synthesis of (±)-7-hydroxylycopodine has been achieved in 5% overall yield. In the key step, a Prins cyclization of a bicyclic keto alkyne in 60% H(2)SO(4) forms a tricyclic dihydroxy amino ketone.     

Synthesis of (±)-7-hydroxylycopodine

A seven-step synthesis of (±)-7-hydroxylycopodine that proceeds in 5% overall yield has been achieved. The key step is a Prins reaction in 60% sulfuric acid that gave the key tricyclic intermediate with complete control of the ring fusion stereochemistry. A one-pot procedure orthogonally protected the primary alcohol as an acetate and the tertiary alcohol as a methylthiomethyl ether. The resulting product was converted to 7-hydroxydehydrolycopodine by heating with KO-t-Bu and benzophenone in benzene followed by acidic workup. During unsuccessful attempts to make optically pure starting material, we observed the selective Pt-catalyzed hydrogenation of the 5-phenyl group of a 4,5-diphenyloxazolidine under acidic conditions and the Pt-catalyzed isomerization of the oxazolidine to an amide under neutral conditions. In attempts to hydroxylate the starting material so that we could adapt this synthesis to the preparation of (±)-7,8-dihydroxylycopodine (sauroine) we observed the novel oxidation of a bicyclic vinylogous amide to a keto pyridine with Mn(OAc)(3) and to an amino phenol with KHMDS and oxygen.     

Total synthesis of (±)-maistemonine, (±)-stemonamide, and (±)-isomaistemonine

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.     

EFFICIENT RESOLUTION OF (±)-1-(9-ANTHRYL)ETHYLAMINE

ABSTRACT

Conditions for efficient resolution of (±)-1-(9-anthryl)ethylamine ((±)-1) by fractional crystallization of its salts with (S)-(+)-mandelic acid (2) are reported. When crystallization was performed by fast addition of chloroform solution of an equivalent of (±)-1 to the hot chloroform solution of (+)-2, crystals of mandelate of (+)-1-(9-anthryl)ethylamine ((R,S)-3) are collected in 56% yield. (R)-(+)-1 (98.6% e.e.) is isolated by extraction from bicarbonate solution of mandelate salt. Ulterior collection of four crops afforded (R,S)-3 with 71.5% cumulative yield and >98% e.e. of (+)-1 in a any single crop. With only 0.5 equivalents of (+)-2 crystallization afforded (R,S)-3 in 47.4% yield and (+)-1 with 98.1% e.e.     

Photochemical Synthesis of Aporphines: (±)-Glaucine, (±)-Norglaucine and (±)-Dehydronorglaucine

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.     

Total Synthesis of (-)-Kaerophyllin,(-)-Hinokinin and (±)-Isohinokinin

Kaerophyllin (1) ,hinokinin (2 )andtheiranalogue isohinokinin (3)belongtothedibenzylbutyrolactone lig nans .Kaerophyllin (1)wasisolatedfromtherootofspot tedcowparsley (ChaerophyllummaculatumWilld .) 1andhinokinin (2 )wasisolatedfromtheheartwoodofLiboce drusformosanaFlorin .2 AccordingtoMacRaeandTow ers ,3afivememberedlactoneringandamethylenedioxylgroupwereimportantstructuralcharacteristicswhichcon tributetotheactivityoflignansasantitumoragents .More over ,anunsaturateddoublebondbetweenC3—…     

Total Synthesis of (±)-Boschnialactone and (±)-Tetrahydroanhydrodesoxyaucubigenin

A total synthesis of (±)-boschnialactone ( 1 ) and (±)-tertahydroanhydrodesoxyaucubigenin ( 2 ) is described and trisubstitued cyclopentenoid 3 is a key intermediate.     

Total synthesis of (±)-7-epi-nemorosone

A concise total synthesis of (±)-7-epi-nemorosone is reported. Our synthetic approach establishes a viable route to polycyclic polyprenylated acylphloroglucinol natural products (PPAP's) bearing a C-7 endo prenyl side chain. Key steps include retro-aldol-vinyl cerium addition to a hydroxy adamantane core scaffold and palladium-mediated deoxygenation.