Reverse Fluorous Solid-Phase Extraction: A New Technique for Rapid Separation of Fluorous Compounds
摘要:
Fluorous-tagged compounds can rapidly be separated from organic (non-tagged) compounds by the new separation technique of reverse fluorous solid-phase extraction (r-fspe). In a reversal of the roles of solid and liquid phases in standard fluorous spe, a mixture is charged to a polar solid phase (standard silica gel) and then eluted with a fluorous solvent or solvent mixture. The organic components of the mixture are retained, while the fluorous components pass.
Ar–nC6F13 and heptafluoroisopropylarenes (Ar–CF(CF3)2) underwent site-selective defluoroallylation. DFT calculation studies revealed that the in situ generated Bu3SnF traps F– to prevent a retroreaction from the unstable perfluoroalkyl radical intermediate, and the radical intermediate favorably reacts with allylic stannanes. The synthesis of a bis(trifluoromethyl)methylene unit containing compound
全氟烷基芳烃的位点选择性和直接 C-F 键转化是通过铱光氧化还原催化剂系统用烯丙基锡烷实现的。本脱氟烯丙基化反应仅在苄基位置通过全氟烷基自由基进行,全氟烷基自由基是从受激光氧化还原催化剂到全氟烷基芳烃的单电子转移产生的。各种全氟烷基都适用:线性全氟烷基取代的芳烃,例如 Ar– n C 4 F 9和 Ar– n C 6 F 13和七氟异丙基芳烃(Ar–CF(CF 3 ) 2)进行了位点选择性脱氟烯丙基化。DFT 计算研究表明,原位生成的 Bu 3 SnF 捕获 F -以防止不稳定的全氟烷基自由基中间体发生逆反应,并且自由基中间体有利于与烯丙基锡烷反应。含双(三氟甲基)亚甲基单元的化合物是一种类似物,可用作预防或治疗糖尿病和炎症性疾病的药物,其合成证明了该反应的实用性。
Palladium catalyzed carboxylation of allylstannanes and boranes using CO<sub>2</sub>
作者:Jianguo Wu、Nilay Hazari
DOI:10.1039/c0cc03191g
日期:——
A family of well-defined (η3-allyl)Pd(L)(carboxylate) (L = PR3 or NHC) complexes are by far the most efficient catalysts reported to date for the catalytic carboxylation of allylstannanes into allylcarboxylates using CO2. The substrate scope of this reaction is extended to both substituted allylstannanes and allylboranes.
迄今为止,一系列定义明确的 (η3-allyl)Pd(L)(carboxylate) (L = PR3 或 NHC)配合物是利用 CO2 催化烯丙基锡烷烃羧化为烯丙基羧酸盐的最有效催化剂。该反应的底物范围扩展到取代的烯丙基锡和烯丙基硼烷。
A highly enantioselective nickel-catalyzed electrochemical radicalallylation reaction was developed in high yields with excellent enantiomeric ratios (up to 93 % ee). The single-electron transfer-based enantioselective electrocatalytic routes would be applied as an alternative approach for the development of a wide range of useful stereocontrolled reactions.
The development of catalytic and enantioselective transformations for the synthesis of all-carbon quaternary stereocenters has long been recognized as a significant challenge in organic synthesis. While considerable progress has been made in asymmetric allylations, their potential to functionalize the commonly used synthon, epoxide, remains largely underexplored. Here we demonstrate the first highly
Reverse Fluorous Solid-Phase Extraction: A New Technique for Rapid Separation of Fluorous Compounds
作者:Masato Matsugi、Dennis P. Curran
DOI:10.1021/ol049040o
日期:2004.8.1
Fluorous-tagged compounds can rapidly be separated from organic (non-tagged) compounds by the new separation technique of reverse fluorous solid-phase extraction (r-fspe). In a reversal of the roles of solid and liquid phases in standard fluorous spe, a mixture is charged to a polar solid phase (standard silica gel) and then eluted with a fluorous solvent or solvent mixture. The organic components of the mixture are retained, while the fluorous components pass.