Palladium(0)‐Catalyzed Directed syn‐1,2‐Carboboration and ‐Silylation: Alkene Scope,Applications in Dearomatization,and Stereocontrol by a Chiral Auxiliary

We report the development of palladium(0)‐catalyzed syn‐selective 1,2‐carboboration and ‐silylation reactions of alkenes containing cleavable directing groups. With B₂pin₂ or PhMe₂Si‐Bpin as nucleophiles and aryl/alkenyl triflates as electrophiles, a broad range of mono‐, di‐, tri‐ and tetrasubstituted alkenes are compatible in these transformations. We further describe a directed dearomative 1,2‐carboboration of electron‐rich heteroarenes by employing this approach. Through use of a removable chiral directing group, we demonstrate the viability of achieving stereoinduction in Heck‐type alkene 1,2‐difunctionalization. This work introduces new avenues to access highly functionalized boronates and silanes with precise regio‐ and stereocontrol.     

磺酰氯参与的基于远端炔基迁移的非活化烯烃炔基化反应

利用自由基参与的远端炔基迁移策略实现了非活化烯烃的炔基化反应. 以磺酰氯为试剂, 在可见光促进下形成三氟甲基自由基或芳基(烷基)磺酰基自由基, 随后加成到非活化烯烃上, 生成烷基自由基中间体, 继而诱导远端炔烃的分子内迁移, 得到三氟甲基炔基化或磺酰基炔基化产物. 该方法具有条件温和、底物易得以及官能团兼容性广等优点.     

杂环光化学Ⅴ.烯类与1,3-二甲基-6-氮杂胸腺嘧啶的光环合加成反应

1974年Sweeton等人首先报道了这一反应^[1]。1981年樊美公等报道了1,3-二甲基-6-氮杂胸腺嘧啶(A)与庚烯-1的反应^[2],1986年又相继报道了含有极性基团的烯类与A的反应。本文通过这类反应合成了新化合物:1,2,4-三氮杂-2,4,6,7-四甲基-3,5-二氧-8-正丁基双环[4,2,0]辛烷(Ⅰ)和1,2,4-三氮杂-2,4,6-三甲基-3,5-二氧叁环[6,4,0,0^7,12]十二烷甲基衍生物(Ⅱ)。     

Construction of the DEF-ring system of nogalamycin and menogaril via an efficient Suzuki-Miyaura reaction

A new approach to the total synthesis of anthracycline natural products, nogalamycin and menogaril, was explored. The goal was to enable late-stage introduction of the EF-ring segment. The new synthetic route has been developed through strategic application of a Suzuki-Miyaura reaction as the key step, which coupled the EF-ring segment with the D-ring to give a 1,1′-disubsitituted alkene in good yield under biphasic conditions. Further manipulation of the coupling product completed the construction of the DEF-ring system.     

活性钛与芳基丙酮的还原偶合反应

羰基化合物还原偶合是形成碳-碳键的一种重要方法。本文首次发现此类反应的产物不仅与反应物本身的结构和还原试剂体系有关，还与操作次序有很大关系，且在活性钛表面反应。     

A Novel Debromination of vic-Dibromides to Alkenes with InCl3（cat.）／Sm System in Aqueous Media

A novel debromination of vic-dibromides to alkenes with InCl3(cat.)/Sm system in aqueous media has been developed. The reaction gives the E-isomers with excellent yields.     

Quantitative XPS analysis of hydrosilated 1‐alkene and 1‐alkyne at terraced,dihydrogen‐terminated, 1 × 1 (100) silicon

A quantitative angle‐resolved XPS analysis was carried out of the carbonaceous films resulting from the derivatization under mild thermal activation of nearly flat, terraced, dihydrogen‐terminated, 1 × 1 (100) Si with 1‐octene or 1‐octyne. The analysis of the C 1s signal gave evidence for the presence of carbon in carbide configuration (Si? C bonds) at the substrate–film interface, in addition to the alkanic carbon and adventitious oxidized carbon (C? O bonds) produced by the oxidizing impurities flawing the reaction. Assuming the surface as uniformly covered, the analysis showed that for both reactants the films were closely packed. Copyright © 2006 John Wiley & Sons, Ltd.     

Diastereoselective Baylis-Hillman reaction: first use of chiral 2,3-epoxy aldehydes as novel electrophiles

Chiral 2,3-epoxy aldehydes have been effectively utilized for the first time as novel electrophiles in Baylis-Hillman reactions with activated alkenes to result in densely functionalized adducts in good yields (61-80%) and in moderate to good diastereoselectivities (40-72% de).     

气相色谱-原子发射光谱和溴加成法联合测定含烯烃汽油中的烯烃单体Ⅰ. 汽油中烯烃保留值的研究

 通过对含烯烃汽油进行溴加成反应，对汽油中烯烃的保留值进行了研究。对171个溴化产物溴代烃进行了定性,并给出了溴代烃所对应的171个烯烃的定性结果,其中对C7前的溴代烃及烯烃组分给出了结构式。定性手段主要依据汽油中混合纯烯烃样品溴化后的气相色谱-质谱联用(GC-MS)数据和气相色谱-原子发射光谱(GC-AED)的元素比数据,确定溴代烃及其对应烯烃单体的分子式,然后利用已有的烯烃单体文献保留值数据、纯烯烃化合物的反应结果并结合碳数规律和沸点规律,确定了烯烃单体化合物的结构。该方法最大的优点是实现了选择性检测烯烃,从而排除了其他烃类化合物对烯烃测试的干扰,因此对于汽油中烯烃的分布有着更直观的反映。     

Manganese(III) acetate based oxidative cyclizations of 3-oxopropanenitriles with conjugated alkenes and synthesis of 4,5-dihydrofuran-3-carbonitriles containing heterocycles

4,5-Dihydrofuran-3-carbonitriles 3a-i were obtained through oxidative cyclizations of 3-oxo-3-phenylpropanenitrile 1a, 3-oxo-3-thien-2-ylpropanenitrile 1b, 3-(2-furyl)-3-oxopropanenitirle 1c, 3-(1-benzofuran-2-yl)-3-oxopropanenitrile 1d, and 4,4-dimethyl-3-oxopropanenitrile 1e mediated manganese(III) acetate with 1,1-diphenyl-1-butene 2a and 1,2-diphenyl-1-pentene 2b. The treatments of these 3-oxopropanenitriles with 2-thienyl substituted alkenes such as 2-[(E)-2-phenylvinyl]thiophene 2c, 2-[(E)-1-methyl-2-phenylvinyl]thiophene 2d, and 2-(1-phenylvinyl)thiophene 2e formed 5-(2-thienyl)-4,5-dihydrofuran-3-carbonitriles 3j-r in good yields (45-93%). As a result, 2-thienyl substituted alkenes formed products in higher yields than phenyl substituted derivatives.