Gold(I)-Catalyzed Addition of Diphenyl Phosphate to Alkynes: Isomerization of Kinetic Enol Phosphates to the Thermodynamically Favored Isomers
作者:Phil Ho Lee、Sundae Kim、Aeri Park、Bathoju Chandra Chary、Sunggak Kim
DOI:10.1002/anie.201001799
日期:2010.9.10
Gold, gold, or …︁ gold? It depends on the (gold) catalyst whether the product of thermodynamic or kinetic control is formed in an unprecedented hydrophosphoryloxylation approach to enolphosphates (see scheme). A third catalyst, [(C6F5)3PAuOTf], was found to be exceedingly effective for the previously unknown isomerization of kineticenolphosphates to the thermodynamicallyfavoredisomers. Tf=tri
黄金,黄金还是…︁黄金?是否以空前的烯醇磷酸盐加氢磷酰氧基化方法形成热力学或动力学控制产物取决于(金)催化剂(参见方案)。发现第三种催化剂[(C 6 F 5)3 PAuOTf]对于动力学烯醇磷酸酯到热力学上有利的异构体的以前未知的异构化非常有效。Tf =三氟甲磺酰基;R =烷基,环己基,Ph。
Organic synthesis with reagents derived from 3R3SiMgMe and MnCl2
R3SiMgMe and MnCl2 are disclosed. (1) The manganese species reacted with terminal acetylenes to give 1,2-disilylated 1-alkenes. Mono- and bis(trimethylsilyl) acetylenes gave tri- and tetrasilylated ethenes, respectively, in good yields. Highly strained tetrakis(trimethylsilyl) ethene has now become easily accessible by this technique. (2) The reaction of alkenyl halides, alkenyl sulfides, and enol phosphates
Iron-Catalyzed Alkenylation of Grignard Reagents by Enol Phosphates
作者:Gérard Cahiez、Olivier Gager、Vanessa Habiak
DOI:10.1055/s-2008-1067194
日期:2008.8
Stereoselective preparation of trisubstituted olefins can be easily performed from an Z/E-mixture of enol phosphates by reacting only the E-isomer with a Grignardreagent in the presence of Fe(acac) 3 . This procedure combines a kinetic differentiation and a stereoselective reaction. The coupling is very chemoselective in the presence of an alkyl chloride, an ester, a ketone or a nitrile.
Aryl triflates were transformed to aryl bromides/iodides simply by treating them with LiBr/NaI and [Cp*Ru(MeCN)(3)]OTf. The ruthenium complex also catalyzed the transformation of alkenyl sulfonates and phosphates to alkenyl halides under mild conditions. Aryl and alkenyl triflates undergo oxidative addition to a ruthenium(II) complex to form eta(1)-arylruthenium and 1-ruthenacyclopropene intermediates, respectively, which are transformed to the corresponding halides.