(±)-12-乙基-13-甲氧基-8,11,13-罗汉松三烯-7-酮和(±)-12-乙基-13-甲氧基-8,11,13-罗汉松三烯的全合成

以α-环柠檬醛(1)为A环合成子,以季盐(2)为C环合成子,经缩合及分子内环化反应得到关键中间体(5).为引入乙基,进行了Friedel-Crafts反应和脱氧反应等,共经7步反应得到了(±)-12-乙基-13-甲氧基-8,11,13-罗汉松三烯-7-酮[(±)-nimbonone](9)及(±)-12-乙基-13-甲氧基-8,11,13-罗汉松三烯(10).     

13-甲氧基-6-羟基钩勿烷-5,8,11,13-四烯-7-酮的首次全合成

以α-环柠檬醛(2)为A环合成子,以间甲氧基苄基氯(3)为C环合成子,经缩合及分子内环化反应得关键中间体6.经1H NMR测试发现化合物6为全顺式结构.化合物6经氧化得双羰基化合物7.将7用t-BuOK/t-BuOH处理后得到烯醇式结构的化合物8.最后将异丙基通过Fride1-Crafts反应一步引入得到目标产物1.     

(S)-(+)-姜黄烯的立体选择性全合成

利用不对称双羟化反应和Raney镍的原位还原,高对映选择性和高产率地实现了(S)-(+)-α-姜黄烯(1)的立体选择性合成.用MsCl保护化合物7a和7b时,发现了有趣的消除和重排反应,得到对应的二烯化合物8.     

(±)-16-羟基-6,7-脱氢铁锈醇甲醚及其类似物的合成

采用AC→ABC的合成策略,以α-环柠檬醛为A环起始原料,通过与C环化合物8缩合、选择性还原及分子内环合得到关键中间体11,再经过官能团修饰和转换,合成了16-羟基-6,7-脱氢铁锈醇甲醚及其3个类似物.     

聚合物支持的三苯基氯硅烷在昆虫性信息素固相合成中的应用

1%二乙烯基苯交联的聚苯乙烯树脂在N,N,N',N'-四甲基乙二胺的存在下用丁基锂进行锂化后与二苯基二氯硅烷反应制得聚苯乙烯支持的三苯基氯硅烷(2).这种聚合物用于一些鳞翅目(lepidoptera)昆虫的性信息素的固相合成.2与1,9-壬二醇,1,10-癸二醇和1,12-十二碳二醇反应分别生成聚合物支持的二醇单硅醚(4a,4b,4c),游离的醇基用Swern试剂(DMSO和草酸酰氯)氧化成聚合物支持的醛(5a,5b,5c),经Wittig缩合反应和用氟离子裂解后分别得到9-十四碳烯醇-1(8a),10-十四碳烯醇-1(8b)和12-十四碳烯醇-1(8c).化合物8经乙酰化后分别得到9-十四碳烯醇-1乙酸酯(9a),其顺式异构体是秋灰夜蛾(S.frugiperda,Smith)的性信息素;10-十四碳烯醇-1乙酸酯(9b),其顺式异构体是橡卷叶蛾(A.semiferamus,Walker)的性信息素;和12-十四碳烯醇-1乙酸酯(9C).9C与四氯化碲反应,硫化钠还原后转化成E-和Z-异构体比例为54:46的亚洲玉米螟(Ostriniafurnicalis)的性信息素.     

新型含噻唑和吡唑环的醛腙类化合物的合成

1-苯基-3-甲基-吡唑-4.-甲醛与氨基硫脲缩合制得醛缩氨基硫脲(Ⅱf～Ⅱh);Ⅱ与α-溴代芳基乙酮反应合成了15个新型的含噻唑和吡唑环的醛腙类化合物(2a～4e),其结构经1 H NMR,IR和元素分析表征.X-射线单晶衍射测试结果表明,2c属斜方晶系,空间群Pbca,晶胞参数a=18.607 9(3)A,b=15...     

含咔唑基的苯并噻唑类铱配合物的合成及其光学性能

以2-溴咔唑为原料,经烷基化、Suziki偶联和环化3步反应合成了新型的环金属配体2-[4-(9-乙基-9H-咔唑-2-基)苯基]苯并噻唑(3);3与三氯化铱和N^N辅助配体(2,2’-联吡啶和1,10-菲啰啉)解离合成了两个新型的离子型环金属铱配合物(5a)和(5b),其结构经1H NMR和ESI-MS表征。用UV-Vis和FL研究了5a和5b的发光性能。结果表明:5a和5b的二氯甲烷溶液为绿色磷光,λex分别为295 nm,450 nm和270 nm,400 nm;λem为570 nm。     

(±)-二氢猕猴桃内酯合成方法的改进

以柠檬醛为原料, 经环化、羟腈化、水解关环和脱水4步反应, 以40.24%的总产率合成了(±)-二氢猕猴桃内酯．     

Di-O-methyl ethers of (-)-agatharesinol,(-)-sugiresinol, (+)-nyasol和(+)-tetrahydronyasol的全合成研究

本文报道了以一种新的方法高产率合成了di-O-methyl ethers of (-)-agatharesinol(1b), ,(-)-sugiresinol(2b), (+)-nyasol (3b)and(+)-tetrahydronyasol (4). 同时，通过首次对(+)-3b 和 (+)-4的合成对(+)-3a的绝对构型进行了确证.     

C-去甲-D-高甾烷的合成工艺改进

以海可吉宁为原料,经乙酰化反应制得海可吉宁乙酸酯(2);2用硼氢化钠还原得到C12-羟基化合物(3);3与对甲苯磺酰氯反应成酯得化合物(4);4经重排反应合成了具有异甾环骨架的烯烃化合物(5),总收率62.6%. 5的结构经1H NMR, MS和IR表征.用正交实验优化了3的合成工艺,使3的收率达95.2%;考察了重排反应溶剂对环内双键[5a(Δ17a(18)-olefin)]和环外双键[5b(Δ13(17a)-olefin)]异构体比例的影响,结果表明,以无水吡啶为溶剂时,5的收率达到86.1%,且5a含量达到100%.     

Chiral Synthesis of 13-Acetyl-12-hydroxy-podocarpane-8, 11,13-triene-7-one

Most diterpenoids exhibit significant bioactivities, such as: antibacterial1,2, antider- matophytic2,3, antioxidant4, etc. 13-Acetyl-12-hydroxy-podocarpane-8,11,13-triene-7-one is a diterpene which has been synthesized by Sukumer et al. from the racemic trans isomer 45. Scheme 1Reagents and conditions: i) n-BuLi, n-hexane , r.t., 4 h (70%); ii) 5% Pd/C, ethanol (95%); iii) BF3.Et2O, CH2Cl2, r.t., 12 h (93%); iv) acetyl chloride, anhydrous AlCl3, -5(C, 4 h (90%); v) CrO3/ HOAc/H2O, r.…     

ENANTIOSELECTIVE TOTAL SYNTHESES OF 13-ACETYL- 12-HYDROXY-PODOCARPANE- 8,11,13-TRIENE-7-ONE

ABSTRACT

A enantioselective total synthetic route to (+)-13-acteyl-12-hydroxy-podocarpane-8,11,13-triene-7-one 1a and (?)-13-acetyl-12-hydroxy-podocarpane-8,11,13-triene-7-one 1b from (S)-(?)-α-cyclocitral 8a and (R)-(+)-α-cyclocitral 8b was developed.     

General approach for the synthesis of 12-methoxy-substituted sarpagine indole alkaloids including (-)-12-methoxy-N(b)-methylvoachalotine, (+)-12-methoxy-N(a)-methylvellosimine, (+)-12-methoxyaffinisine, and (-)-fuchsiaefoline

[structures: see text] The enantiospecific synthesis of 7-methoxy-D-tryptophan ethyl ester was completed by combination of the Larock heteroannulation process with a Sch?llkopf-based chiral auxiliary in good yield. This ester was then employed in the first regiospecific, stereospecific total synthesis of (+)-12-methoxy-N(a)-methylvellosimine, (+)-12-methoxyaffinisine, (-)-fuchsiaefoline, and 12-methoxy-N(b)-methylvoachalotine in excellent overall yield. The asymmetric Pictet-Spengler reaction and enolate-driven palladium-catalyzed cross-coupling processes served as key steps. The quaternary center at C16 of 12-methoxy-N(b)-methylvoachalotine was established via the Tollens reaction between (+)-12-methoxy-N(a)-methylvellosimine and formaldehyde to form diol 17. The two prochiral primary alcohols in diol 17 were differentiated by the oxidative cyclization(DDQ) of the hydroxyl group at the axial position of 17 with the benzylic postion at [C6] to form a cyclic ether [C6-O17]. After oxidative formation of the alpha-ester at C16, the ether bond was reductively cleaved with TFA/Et3SiH in high yield. The DDQ-mediated oxidative cyclization and TFA/Et3SiH reductive cleavage served as protection/deprotection steps in order to provide a versatile entry into the voachalotine alkaloids.     

Totalsynthese von (+)-D-Homoöstron-3-methyläther

Total Synthesis of (+)-D-Homoestrone 3-methyl ether A novel total synthesis of (+)-D-homoestrone 3-methyl ether ( 21 ) is described starting from (S)-8a-methyl-3,4,8,8a-tetrahydro-2H, 7H-naphthalene-1,6-dione ( 1 ) as a chiral synthon for the rings C and D. The key step involves alkylation of the derived 3 with m-methoxyphenacyl bromide ( 4 ) as an AB-building block to give the dioxo-secosteroid 5 . Hydrogenation of 5 affords the trans-decalone 11 . As by-products the epimeric cis-decalones 12 and 13 were characterized. Cyclization of 11 leads under kinetic control predominantly to the Δ⁹⁽¹¹⁾-tetraene 14 . Catalytic hydrogenation of 14 and subsequent modification in ring D give the title compound 21 . It was found that 14 and also the derived Δ⁸-isomer 15a add hydrogen from the α-face of the molecule to an extent of about 80%. The 8α-D-homoestrone derivatives 20a and 23 as well as the 9β-isomers 19a and 22 were characterized.     

Sequential Benzylic Oxidation of Naloxone 3-Methyl Ether

Naloxone 3-methyl ether was selectively oxidized by treatment with cerium ammonium nitrate in aqueous acetonitrile at ambient temperature to provide the 10-(S)-hydroxy adduct. The stereochemistry of the oxidation product was proven by single crystal X-ray structure determination. The Dess-Martin periodinane further oxidized the 10-hydroxy to the 10-keto analog. Deprotection formed 10-ketonaloxone as an analytical reference standard.     

A New Enantioselective Total Synthesis of Natural Vincamine via an Intramolecular Mannich Reaction of an Silyl Enol Ether

Natural Vincamine ( 1 ) has been synthesized in an enantioselective manner starting from the ethylpentenal 7 . In the key step a mixture of the diastereoisomeric racemates, 14 and 15 , was directly obtained from the silyl enol ether 11 and the dihydro-β-carboline 12 by the way of an intramolecular Mannich reaction of the intermediate 13 (Scheme 4). The undesired stereoisomers, 14 and 15b , were recycled to 15a using the related reversible Mannich reaction 18 ? 14 + 15 , followed by crystallization of the salt from 15a and (+)malic acid. 15a was converted to natural vincamine ( 1 ) in several steps including the known transformation 20→1 .     

Syntheses of (+)- and (–)-Methyl 8-Epinonactate and (+)- and (–)-Methyl Nonactate

In four synthetic steps, (+)- and (–)-methyl 8-epinonactate ((+)- and (–)? 4 ) have been derived from (+)- and (–)-7-oxabicyclo[2.2.1]heptan-2-one ((+)- and (–)? 9 ), respectively. The (+)- and (–)-methyl nonactate ((+)- and (–)? 3 ) were obtained from (+)- and (–)? 4 , respectively, by Mitsunobu displacement reactions. Optical resolution of (±)? 9 via chromatographic separation of the corresponding N-methyl-S-alkyl-S-phenylsulfoximides 24 and 25 yielded the starting materials (+)- and (–)? 9 , respectively.