A Stereoselective Synthesis of Substituted Allyl Alcohol by Threecomponent Rection of Acetylenic Sulfone, Phenylselenomagnesium Bromide and Ketones

Phenylseleno and sulfonyl substituted allyl alcohols were synthesized stereoselectively by the three-componem reaction of acetylenic sulfone, phenylselenomagnesium bromide and ketones in one-pot.     

格氏试剂异构偶联法合成辅酶Q10

报道了一种利用2-甲基-3-氯-4-(2'-甲基-3',4',5',6'-四甲氧基苯)丁烯的格氏试剂与茄尼基溴发生异构偶联, 再氧化合成辅酶Q10的新方法. 发现了烯丙式格氏试剂与卤代烷经过六元环过渡态的异构偶联反应.     

手性烯丙基胺的合成进展

综述了近年来手性烯丙基胺的合成进展, 重点介绍了催化剂配体对化学选择性和对映选择性的影响, 并阐述了各种类型的反应机理.手性; 烯丙基胺; 催化     

利用Grignard试剂的甲酰化反应合成对甲氧基苯甲醚

二取代苯并咪唑盐;利用Grignard试剂的甲酰化反应合成对甲氧基苯甲醚     

对甲基苯甲醛的Grignard试剂合成法

二甲基苯并咪唑盐;对甲基苯甲醛的Grignard试剂合成法     

双环戊二烯基二氯化钛催化下格氏试剂与偕二卤代烷的反应

近年来,双环戊二烯基二氯化钛在有机合成中的应用得到迅速发展,从而开发了多种新型反应。其中双环成二烯基二氯化钛催化下,Grignard试剂的还原反应是研究得极为广泛的一类新反应。Cp_2Ticl_2/RMgX体系可以还     

烯丙基砜的合成与表征

以三种烯丙醇为起始原料 ,经溴代生成烯丙基溴 ,然后与无水苯亚磺酸钠发生亲核取代反应生成烯丙基砜。烯丙基溴与烯丙基砜在相转移催化下的偶联反应也可合成新的烯丙基砜。作者用这两种方法合成了六种烯丙基砜。初步探讨了反应温度 ,催化剂等对反应的影响。产物结构经IR ,1 HNMR等波谱分析确证。     

Copper‐Free Asymmetric Allylic Alkylation with a Grignard Reagent: Design of the Ligand and Mechanistic Studies

The Cu‐free asymmetric allylic alkylation, catalysed by NHC, with Grignard reagents is reported on allyl bromide derivatives with good results. The enantioselectivity was quite homogeneous (around 85 % ee) on large and various substrates, regardless of the nature of the Grignard reagent. The formation of stereogenic quaternary centres was highly regioselective for both aliphatic and aromatic derivatives with good enantiomeric excess (up to 92 % ee). The methodology developed was found to be complementary with the Cu‐catalysed version. Several new NHCs were tested with improved efficiency. In addition, mechanistic studies, using NMR spectroscopy, led to the discovery of the catalytically active species.     

色谱联用技术表征双格氏反应进程

探讨双格氏试剂的结构表征方法及其制备过程跟踪分析。以1,4-二溴-2,5-对苯二甲醚为原料,在无水四氢呋喃溶剂中制备得到相应双格氏试剂,采用气相色谱–红外、气相色谱–质谱联用技术对1,4-二溴-2,5-二甲氧基苯的双格氏试剂及其反应过程中的产物进行结构表征和进程跟踪分析。结果表明,反应体系中同时存在双格氏、单格氏产物,并随着反应进行,单格氏产物进一步转化为双格氏产物。该实验结果可以对双格氏反应机理的研究提供理论数据。     

Cp2TiCl2催化下Grignard试剂与芳醛反应的研究

Meunier 等曾研究了 Cp_2TiCl_2催化下,格氏试剂对卤代烷和羰基化合物的还原反应,并报道了与芳环或碳-碳双键或碳-碳三键共轭的羰基化合物不被格氏试剂还原。我们却发现,在较低温度下,这些芳醛或与碳-碳重键共轭的羰基化合物也会被还原,特别是在芳环上有吸电子取代基时,还原产物的产率很高。     

Synthesis of C-Glucosides from Grignard Reagents Prepared by Activated Magnesium

l-α-biaomo-2,3,4,6-tetra-O-acetyl-D-giucopyranose reacts with Grignard eagents prepared frorn the acnvated magnesium under very mild condition to ellord C- glucosides in a very high yield compared with Grignard Reagent prepared from usual method.β-anomer predominates in the reaction, mixture The configuration of anomers was assigned by 13C NMR spectra.     

Cu‐Catalyzed Asymmetric Allylic Alkylation of Phosphonates and Phosphine Oxides with Grignard Reagents

An efficient and highly enantioselective copper‐catalyzed allylic alkylation of phosphonates and phosphine oxides with Grignard reagents and Taniaphos or phosphoramidites as chiral ligands is reported. Transformation of these products leads to a variety of new phosphorus‐containing chiral intermediates.     

Reaction of Alkanesulfinyl Chloride with Grignard Reagents： a Convenient Synthesis of Alkyl Sulfoxides

Alkyl sulfoxides were synthesized in good yields from the reaction of alkanesulfinyl chloride with Grignard reagents in the presence of zinc chloride.     

CuI-catalyzed tandem carbomagnesiation/carbonyl addition of Grignard reagents with acetylenic ketones: Convenient access to tetrasubstituted allylic alcohols

Highly functionalized tetrasubstituted allylic alcohols were prepared conveniently by CuI-catalyzed tandem carbomagnesiation/carbonyl addition of Grignard reagents with acetylenic ketones. The obtained allylic alcohols can be further transformed to polysubstituted indenes by intramolecular cyclization.     

Stereoselective Synthesis of δ-Selanyl Allylic Alcohols by Hydrozirconation of Propargyl Selenides

Hydrozirconation of propargyl selenides afford(E)-3-selanyl vinylzirconocenes chlorides 2.Intermediates 2 reacted with aldehydes to obtain δ-selanyl allylic alcohols.     

Synthesis of Primary Amines by One-Pot Reductive Amination of Aldehydes

We report here a novel, one-pot, two-step reductive amination of aldehydes for the atom-economical synthesis of primary amines. The amination step has been carried out with hydroxylammonium chloride and does not require the use of a base. In the subsequent reduction step, a metal zinc/hydrochloride acid system has been used. This method is applicable to both aliphatic and aromatic aldehydes. The operational simplicity, the short reaction times, and the mild reaction conditions add to the value of this method as a practical alternative to the reductive amination of aldehydes.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Three-Component Reaction of Triphenylphosphine,Acetylenic Esters,and Arylsulfonyl Hydrazides or Aryl Hydrazines: An Efficient One-Pot Synthesis of Stable β-Nitrogen-Substituted Phosphorus Ylides

The three-component reaction between dialkyl acetylenedicarboxylates and triphenylphosphine in the presence of arylsulfonyl hydrazides or aryl hydrazines produces highly functionalized, salt-free phosphorus ylides in excellent yields.     

Regio- and stereoselective synthesis of tetrasubstituted allylic alcohols by three-component reaction of acetylenic sulfone, dialkylzinc, and aldehyde

(Z)-Tetrasubstituted allylic alcohols bearing sulfonyl group were synthesized regio- and stereoselectively by alkylzincation of acetylenic sulfone followed by addition to aldehyde.     

Stereoselective Synthesis of Tertiary Allylic Amines by Titanium-Catalyzed Hydroaminoalkylation of Alkynes with Tertiary Amines

Intermolecular hydroaminoalkylation reactions of symmetrical and unsymmetrical alkynes with tertiary amines take place in the presence of catalytic amounts of TiBn₄, Ph₃C[B(C₆F₅)₄], and a sterically demanding aminopyridinato ligand precursor. The resulting products, synthetically and pharmaceutically useful tertiary β,γ-disubstituted allylic amines, are formed in convincing yields and with excellent stereoselectivity. Particularly promising for future applications is the fact that even the industrial side product trimethylamine can be used as a substrate.     

Stereoselective synthesis of vinyl sulfones by carbomagnesiation of acetylenic sulfone in the presence of CuCN

Carbomagnesiation of acetylenic sulfone in the presence of catalytic amount of CuCN gave α-sulfonyl vinyl magnesium reagent, which further reacted with aldehydes to afford polysubstituted vinyl sulfones in moderate to good yields.