Microwave-Assisted Cross-Metathesis of Unsaturated Thiocyanates: Application to the Synthesis of Thiocyanatins A and B and Analogues
摘要:
硫氰酸铂 B 和相关二硫代氰酸酯的合成是通过不饱和硫氰酸盐在钌催化剂的促进下进行交叉偏析来实现的。反应的效率在很大程度上取决于催化剂的性质、烯基链的长度和活化方式(传统加热或微波活化)。在后一种情况下,双键发生了异构化,改变了反应的进程。另外,硫氰酸盐 A 和 B 也分别只需三步和两步就能从现成的对甲苯磺酸盐中合成。
Direct Synthesis of Nitriles from Aldehydes Using an O-Benzoyl Hydroxylamine (BHA) as the Nitrogen Source
摘要:
The direct synthesis of nitriles from commercially available or easily prepared aldehydes has been achieved. O-(4-CF3-benzoyl)-hydroxylamine (CF3-BHA) was utilized as the nitrogen source to generate O-acyl oximes in situ with aldehydes, which can be converted to a nitrile with the assistance of a Bronsted acid. Several aliphatic, aromatic, and alpha,beta-unsaturated nitriles that contain different functional groups were prepared in high yields (up to 94% yield). This method has notable advantages, such as simple and mild conditions, high yields, and good functional group tolerance.
[EN] SYNTHESIS OF STRAIGHT-CHAIN LEPIDOPTERAN PHEROMONES THROUGH ONE- OR TWO- CARBON HOMOLOGATION OF FATTY ALKENES<br/>[FR] SYNTHÈSE DE PHÉROMONES DE LÉPIDOPTÈRES À CHAÎNE DROITE PAR HOMOLOGATION D'UN OU DEUX ATOMES DE CARBONE D'ALCÈNES GRAS
申请人:PROVIVI INC
公开号:WO2020018581A1
公开(公告)日:2020-01-23
Methods for the preparation of alkenes including insect pheromones are described. The methods include homologation reactions employing reagents such as 1,3-diesters, epoxides, cyanoacetates, and cyanide salts for elongation of starting materials and intermediates by one or two carbon atoms. The alkenes include insect pheromones useful in a number of agricultural applications.
Synthesis of fused tetrazole- and imidazole derivatives via iodocyclization
作者:Fredrik Ek、Lars-Göran Wistrand、Torbjörn Frejd
DOI:10.1016/s0040-4020(03)00818-4
日期:2003.8
The possibility to prepare fused tetrazole- and imidazole derivatives by iodocyclization in moderate to excellent yields is demonstrated. In some examples the cyclizations were not following Baldwin's rules entirely, i.e. exo-selectivity. Nucleophilic substitution of the formed iodides gave different results depending on the hardness of the nucleophile. Thus, elimination of the iodide could be a problem
Chemoselectivity in the chromium(II)-mediated synthesis of E-alkenylstannanes from aldehydes and Bu3SnCHBr2
作者:David M. Hodgson、Lee T. Boulton、Graham N. Maw
DOI:10.1016/s0040-4039(00)76805-5
日期:1994.4
The synthesis of functionalised E-alkenylstannanes fromaldehydes and a mixture of Bu3SnCHBr2, LiI and CrCl2 is described.
描述了由醛和Bu 3 SnCHBr 2,LiI和CrCl 2的混合物合成官能化的E-链烯基锡烷。
Microwave-Assisted Cross-Metathesis of Unsaturated Thiocyanates: Application to the Synthesis of Thiocyanatins A and B and Analogues
作者:Olivier Piva、Fanny Cros、Béatrice Pelotier
DOI:10.1055/s-0029-1217089
日期:2010.1
The syntheses of thiocyanatin B and related dithiocyanates have been carried out by cross metathesis of unsaturated thiocyanates promoted by a ruthenium catalyst. The efficiency of the reaction depends strongly on the nature of the catalyst, the length of the alkenyl chain, and the mode of activation (conventional heating or microwave activation). In the later case, isomerization of double bonds took place and altered the course of the reaction. Alternatively, thiocyanatins A and B were synthesized by only a three-step and a two-step procedure, respectively, from readily available tosylates.
硫氰酸铂 B 和相关二硫代氰酸酯的合成是通过不饱和硫氰酸盐在钌催化剂的促进下进行交叉偏析来实现的。反应的效率在很大程度上取决于催化剂的性质、烯基链的长度和活化方式(传统加热或微波活化)。在后一种情况下,双键发生了异构化,改变了反应的进程。另外,硫氰酸盐 A 和 B 也分别只需三步和两步就能从现成的对甲苯磺酸盐中合成。
Scope of the chromium(II)-mediated synthesis of E-alkenylstannanes from aldehydes and Bu3SnCHBr2
作者:David M Hodgson、Lee T Boulton、Graham N Maw
DOI:10.1016/0040-4020(95)00086-n
日期:1995.3
The synthesis of E-alkenylstannanes fromaldehydes and a mixture of Bu3SnCHBr2, LiI and CrCl2 is described. A mechanism is proposed to account for the alkene geometry in chromium(II)-mediated alkene synthesis which involves stereoselective addition by a gem-dichromium reagent to an aldehyde followed by a stereospecific elimination step.