（E,E）—3,7—二甲基—2,6—癸二烯—1,10—二醇的高立体选择？…

1969年 Meinwald等 [1] 从一系列雄性蝴蝶的“hair pencils”中分离得到一组信息素成分 ,包括一类新颖的开链倍半萜骨架化合物 1— 3.尽管这些化合物在结构上与香叶醇相似 ,但利用香叶醇为原料进行合成的报道 [2～ 5] 还不多见 .本文以香叶醇为原料 ,报道了化合物 3的一条简便、高立体选择性的合成路线 .其关键反应步骤是 2 ,3-环氧醇的碘代重排反应和烯丙基烯基醚的克莱森重排反应 .a.Ac2 O,Pyridine,r.t.,2 h,yield 98% ;b.Se O2 ,t-Bu OOH,CH2 Cl2 ,r.t.,3 h,yield 73 % ;c.VO( acac) 2 ,t-Bu OOH,reflux,2 h,yield 90 % ;d.Ph3…     

9-氧代桉烷-4-烯-3-酮类似物的DDQ脱氢重排反应机理研究

我们在研究 9-氧代桉烷 - 4-烯 - 3 -酮类化合物的 2 ,3 -二氯 - 5 ,6 -二腈基 - 1 ,4-苯醌 (DDQ)脱氢反应时[1] ,发现 1 4-降桉烷 - 4,1 1 -二烯 - 3 ,9-二酮及其 1 0 - Epimer在 DDQ脱氢条件下发生迁移重排反应 ,生成酚类化合物 .反应式如下 :DDQ脱氢反应已被详细研究 ,并被广泛地用于有机合成中 [2～ 5] ,但这种脱氢重排反应尚未见文献报道 .为了深入研究该反应 ,提出可能的重排机理 .我们参照文献 [6～ 1 0 ]方法 ,用 MVK和 EVK与相应的 2 -甲基 - 1 ,3 -二酮进行 Robinson成环反应 ,合成了一系列具有类似结构的化合物 ,并与 DD…     

6-溴-N-芳基噻吩[2,3-d]并嘧啶-4-胺类化合物的合成新方法

研究了6-溴-N-[3-氯-4-(3-氟苄氧基)苯基]噻吩[2,3-d]并嘧啶-4-胺的合成新方法.以相对廉价的2,5-二羟基-1,4-二噻烷和丙二腈为原料,依次通过Gewald反应、芳环溴代、缩合、环合以及Dimroth重排四步反应得到目标产物6-溴-N-[3-氯-4-(3-氟苄氧基)苯基]噻吩[2,3-d]并嘧啶-4-胺,总产率为56.9%.用1H NMR,IR,MS和HRMS对产物进行了结构表征.并应用该方法,合成了一系列的6-溴-N-芳基噻吩[2,3-d]并嘧啶-4-胺类化合物.研究表明该方法具有原料易得、操作简便、收率较高,且产物容易分离纯化等优点.     

2-取代-3,4-二氢-1-异喹啉酮的合成和舒张血管活性

以3-羟基-4-甲氧基苯甲酸甲酯等为原料, 通过烯丙基醚化、Claisen重排、氧化、与伯胺反应(生成Schiff碱)、还原、分子内酯的胺解六步反应合成了一系列2-取代-3,4-二氢-1-异喹啉酮类化合物. Schiff碱的制备、还原、酯的胺解三步在“一锅”内完成. 采用1H NMR, MS和元素分析对目标化合物的结构进行了表征. 离体动脉环张力实验证明此类化合物具有明显舒张血管的作用.     

辅酶Q10的重要中间体——(2E,6E)-8-乙酰基-2,6-甲基-2,6-辛二烯-1-醇的合成

在CH2Cl2-H2O-NaCl溶液中,香叶醇的末端烯丙基经电解转变成烯丙基氯化物(2),2与二甲胺反应生成末端烯丙基胺(3),3再用过氧乙酸氧化形成烯丙基二甲基胺氧化物后,通过[2,3]-σ重排,再经锌粉还原得到辅酶Q10的重要中间体——2E,6E)-8-乙酰基-2,6-甲基-2,6-辛二烯-1-醇(7),7的结构经1H NMR和IR表征,且全为末端反式烯丙型醇。     

1,2-二(对-甲苯基)-1,2-二甲基二硅桥连二环戊二烯基四羰基二铁的合成及热重排反应

Cl2MeSiSiMeCl2与环戊二烯基锂及对甲苯基溴化镁反应, 生成C5H5(p-Tol)MeSiSiMe(p-Tol)C5H5. 后者再与五羰基铁反应, 得到标题化合物[η5, η5-C5H4(p-Tol)MeSiSiMe(p-Tol)C5H4]Fe2(CO)2(μ-CO)2(3); 同时还得到两个单硅桥连副产物[η5, η5-(p-Tol)2MeSiSiMe(C5H4)2]Fe2(CO)2(μ-CO)2(4)和[η5, η5-(p-Tol)Me2SiSiMe(C5H4)2]Fe2(CO)2(μ-CO)2(5). 化合物3中顺式异构体(3a)占绝对优势, 可通过简单重结晶分离出纯品. 化合物3a在加热条件下发生分子内的硅硅键和铁铁键之间的复分解重排反应, 生成[η5-(p-Tol)MeSiC5H4Fe(CO)2]2(6). 该产物为顺反异构体的混合物(顺反异构体的摩尔比为4:3), 表明重排反应不涉及协同历程. 利用X射线衍射法测定了化合物4的分子结构.     

6-烯-8-羰基-1-叔丁氧基羰基氮杂螺[4,4]壬烷的合成

以烯丙基脯氨酸甲酯(1)为起始原料, 经7步反应以42%的总收率得到了三尖杉碱合成中的重要中间体6-烯-8-羰基-1-叔丁氧基羰基氮杂螺[4,4]壬烷(7). 关键反应为构筑螺环季碳的[2,3]斯蒂文森重排(Stevens rearrangement)及烯丙基双键加氧的酸内酯化反应(Acid-lactonization reaction).     

11,2,4-三嗪类化合物的研究XXⅢ.6-氮杂嘌呤衍的合物

本文报道3-甲硫基-5-取代芳基-咪唑并[4,5-e]--1,2,4-三嗪-6-[7H]- 酮化合物的合成,成功地利用Curtius重排得到了高收率的6-氮杂嘌呤衍生物.     

11,2,4-三嗪类化合物的研究XXⅢ.6-氮杂嘌呤衍的合物

本文报道3-甲硫基-5-取代芳基-咪唑并[4,5-e]--1,2,4-三嗪-6-[7H]- 酮化合物的合成,成功地利用Curtius重排得到了高收率的6-氮杂嘌呤衍生物.     

红霉素9,11-亚胺醚和乙腈分子加合物的合成和晶体结构

通过控制红霉素A (E)肟的贝克曼重排反应条件合成了一种关键中间体红霉素9,11-亚胺醚, 该化合物可与乙腈形成稳定的分子加合物(摩尔比为1∶1), 未见文献报道. 阐述了该化合物的合成、晶体结构、晶体学数据和结构参数. 该化合物为无色透明晶体, 属单斜晶系, 空间群P2₁. 对该加合物和已知化合物红霉素6,9-亚胺醚晶体结构的对照解析, 有助于对重排反应机理、异构化机理和两异构体还原差异性的分析, 对重排反应和还原反应起到积极的指导作用.     

Asymmetric total syntheses of heliannuol E and epi-heliannuol E

Asymmetric total syntheses of heliannuol E and epi-heliannuol E were achieved in 10 and 13 steps, respectively, from the commercially available starting materials. The syntheses feature an intramolecular attacking on the sulfate to form the dihydropyran ring of heliannuol E and an acyl transfer-secondary carbocation capture sequence to construct the dihydropyran ring of epi-heliannuol E.     

Highly Stereoselective Synthesis of (E, E)-3,7-Dimethyl-2,6-decadiene-1, 10-diol

Thediol1,aqueenbutterflypheromonewasisolatedfromqueenbutterfly(Danausgillippusbelenice).SynthesesofthiscompoundwerereportedfromtheorthoesterClaisenrearrangement2,therearrangementofallylsiloxylinylether3andtheanionic[2,3]-sigmatropicrearrangementofallylicsulfide4.Inlightoftheirbiologicalinterest,itseemeddesirabletodesignamoreefficientroutetothissubstance.Thus,wewishtoreportashort,stereoselectivesynthesisof1utilizingthe1,3-transformationof2,3-epoxyalcoholandtheClaisenrearrangementofallylvinylet…     

Preparation of 1,3-Dienes,its Application to the Synthesis of (Z,E)-9,11-Tetradecadienyl Acetate and (E,E)-10,12-Hexa-decadienal: Sex Pheromones of Cotton Pests

E-2-Penten-4-yn-1-ol (3) has been utilized as a source for 1,3-diene systems by employing lithium amide induced alkylation, and curpous iodide catalysed Grignard coupling reaction as key steps. Its application for the synthesis of (Z,E)-9,11-tetradecadienyl acetate and (E,E)-10,12-hexadecadienal is described.     

Total syntheses of bengamides B and E

Total syntheses of the cytotoxic marine natural products bengamides B and E are described. Both bengamides are prepared via amide coupling of a protected polyhydroxylated lactone intermediate 9 with a suitably substituted aminocaprolactam intermediate. Lactone 9 is prepared in five steps from commercially available alpha-D-glucoheptonic gamma-lactone. The key reactions are a selective deprotection of a 1,2-acetonide in the presence of a 1,3-acetonide and an (E)-selective olefination of an unstable aldehyde using a gem-dichromium reagent. The bengamide B lactam intermediate 10 is prepared in seven steps from commercially available (5R)-5-hydroxy-L-lysine (12). The desired S-configuration at the gamma-OH lactam position is established using the Mitsunobu reaction.     

Total synthesis of dispyrin, purpurealidin E, and aplysamine-1

Bromotyrosine alkaloids dispyrin (1), purpurealidin E (2), and aplysamine-1 (3) isolated from marine sponge, were synthesized from commercially available tyramine (4) as a common starting material. The overall yield was 18%, 39%, and 22% for 1 from 4 in 5 steps, 2 in 5 steps, and 3 in 6 steps, respectively.     

Convergent and Stereoselective Synthesis of Sarcophytol-Q Precursor: (11S)-3,7,11,15-Tetramethyl-11-hydroxy-14-oxo-3E,7E,12E-hexadecatrienal

A chiral precursor of sarcophytol-Q, (11S)-3,7,11,15-tetramethyl-11-hydroxy-14-oxo-3E,7E,12E-hexadecatrienal, was synthesized in a convergent and stereoselective manner starting from geraniol and 4-hydroxy-2-butanone in nine steps. The key steps were asymmetric Sharpless epoxidation, base-induced dehydrohalogenation rearrangement of chiral epoxy chloride 5 and the phase transfer catalytic coupling reaction of allylic phenyl sulfone 4 with chiral allylic chloride 3 .     

Stereospecific Synthesis of (E,E)-9, 11, 13-Tetradecatrienyl Acetate and Aldehyde (Geometrical Isoers of the Major Components of Two Sex Pheromones of Lepidoptera)

A stereospecific synthesis of (E,E)-9, 11, 13-tetradecatrienyl acetate and aldehyde is described. The key steps are two sequential palladium-catalyzed cross-coupling reactions between adequate organometalic reagents and the (E)-1,2-dibromoethylene.     

Biomimetic total synthesis of litseaverticillols B, E, I, and J and structural reassignment of litseaverticillol E

[reaction: see text] The first total synthesis of litseaverticillols B (1), E (2), I (4), and J (5) as well as the structural reassignment of litseaverticillol E (2) have been achieved by means of a biomimetic sequence of transformations during which a [4 + 2]-initiated reaction cascade and an ene reaction, both involving singlet oxygen ((1)O(2)), formed key steps. The reassignment of the structure of litseaverticillol E (3) to include an allylic hydroperoxide provides strong support for our biogenetic hypothesis.     

De novo asymmetric synthesis of fridamycin E

A de novo asymmetric synthesis of (R)- and (S)-fridamycin E has been achieved. The entirely linear route required only nine steps from commercially available starting materials (16% overall yield). Key transformations included a Claisen rearrangement, a Sharpless dihydroxylation and a cobalt-catalyzed epoxide carbonylation to give a β-lactone intermediate. Antibacterial activities were determined for both enantiomers using two strains of E. coli, with the natural (R)-enantiomer showing significant inhibition against a Gram-(+)-like imp strain (MIC = 8 μM).