tris(pentafluorophenyl)borane, B(C6F5)3, and BF3·Et2O are shown to catalyze the regioselective hydrothiolation of a wide range of terminal 1-aryl-1,3-dienes. In the case of internal 1,3-dienes, B(C6F5)3 is by far the better catalyst than BF3·Et2O. The process features mild reaction conditions, broad scope, and low catalyst loading, and it can be scaled up quickly over a short reaction time. The reactions are rate-limited
报道了用于合成仲和叔烯丙基硫醚的无过渡金属的1,3-二烯氢硫醇化反应。硼路易斯酸三(五氟苯基)硼烷,B(C 6 F 5)3和BF 3 ·Et 2 O已显示出催化范围广泛的末端1-芳基-1,3-二烯的区域选择性氢硫醇化反应。在内部1,3-二烯的情况下,与BF 3 ·Et 2相比,B(C 6 F 5)3是更好的催化剂。O.该工艺的特点是反应条件温和,适用范围广,催化剂用量低,并且可以在较短的反应时间内迅速扩大规模。如高水平DFT计算所示,反应是通过1,3-二烯与硫醇-硼路易斯酸配合物的1-芳基定向质子化,然后将硫化物阴离子转移到所得的烯丙基阳离子上来进行的,从而限制了反应的速率。
Chemo- and regioselective reductive transposition of allylic alcohol derivatives <i>via</i> iridium or rhodium catalysis
作者:Rylan J. Lundgren、Bryce N. Thomas
DOI:10.1039/c5cc07993d
日期:——
The selective, catalytic deoxygenation of alcohols remains a persistent challenge in organic synthesis. Pd-catalyzed formate reduction and diazene-mediated reductivetransposition are both valuable strategies for the selective deoxygenation of allylic...
Iron-catalysed, hydride-mediated reductive cross-coupling of vinyl halides and Grignard reagents
作者:Bryden A. F. Le Bailly、Mark D. Greenhalgh、Stephen P. Thomas
DOI:10.1039/c1cc14622j
日期:——
hydride-mediated reductive cross-coupling reaction has been developed for the preparation of alkanes. Using a bench-stable iron(II) pre-catalyst, reductive cross-coupling of vinyl iodides, bromides and chlorides with aryl- and alkyl Grignardreagents successfully gave the products of formal sp(3)-sp(3) cross-coupling reactions.
generated in dichloromethane from equimolar amounts of vanadium trichloride and Grignardreagents underwent the chemoselective cross-coupling reaction with acid chlorides leading to the corresponding ketones. Treatment with allyl halides resulted in allylation of organovanadium compounds. In the case of propargyl bromide, regioselective displacement occurred to produce allene derivatives.
Bidentate Hydroxyalkyl NHC Ligands for the Copper-Catalyzed Asymmetric Allylic Substitution of Allyl Phosphates with Grignard Reagents
作者:Magaly Magrez、Yann Le Guen、Olivier Baslé、Christophe Crévisy、Marc Mauduit
DOI:10.1002/chem.201203969
日期:2013.1.21
Demonstrating their potential: Bidentate alkoxy NHC ligands have been used in the copper‐catalyzed asymmetricallylic alkylation of allylphosphates with Grignard reagents (see scheme). The method provides access to tertiary and quaternary chiral centers with high regio‐ and enantioselectivity. The system is also applied to the synthesis of chiral E,E‐dienes, a key structural motif prevalent in natural