Tetrapropylammonium Perruthenate Catalyzed Glycol Cleavage to Carboxylic (Di)Acids
摘要:
A new method to accomplish glycol cleavage to carboxylic (di)acids in one step using catalytic amounts of tetrapropylammonium perruthenate (TPAP) together with N-methylmorpholine N-Oxide (NMO) as the stoichiometric oxidant is presented. In addition to regenerating the active catalyst, the N-oxide stabilizes intermediary carbonyl hydrates and thereby shifts a crucial equilibrium. The mild oxidation protocol is applicable to a broad range of substrates providing the respective acids, diacids, or keto acids in high yields.
Catalytic Intermolecular Coupling of Rhodacyclopentanones with Alcohols Enabled by Dual Directing Strategy
作者:Ya-Lin Zhang、Rui-Ting Guo、Jia-Hao He、Xiao-Chen Wang
DOI:10.1021/acs.orglett.9b01420
日期:2019.6.7
A catalytic carbonylative ring-opening and functionalization reaction of poorly activated cyclopropanes has been developed. The key achievement of this work is the accomplishment of an unprecedented effective intermolecular trapping of the rhodacyclopentanone intermediate, which is derived from rhodium-mediated carbonylative insertion of poorly activated cyclopropanes, by an external reactant. The
The Direct Conversion of α-Hydroxyketones to Alkynes
作者:Francesca Ghiringhelli、Lukas Nattmann、Sabine Bognar、Manuel van Gemmeren
DOI:10.1021/acs.joc.8b02941
日期:2019.1.18
Alkynes are highly important functional groups in organic chemistry, both as part of target structures and as versatile synthetic intermediates. In this study, a protocol for the directconversion of α-hydroxyketones to alkynes is reported. In combination with the variety of synthetic methods that generate the required starting materials by forming the central C–C bond, it enables a highly versatile
Homogeneous cis-dihydroxylation and epoxidation of olefins with high H2O2 efficiency by mixed manganese/activated carbonyl catalyst system
作者:Jelle Brinksma、Lizette Schmieder、Gerbert van Vliet、Rob Boaron、Ronald Hage、Dirk E De Vos、Paul L Alsters、Ben L Feringa
DOI:10.1016/s0040-4039(02)00292-7
日期:2002.4
[Mn2O3(tmtacn)2](PF6)2 (tmtacn=1,4,7-trimethyl-1,4,7-triazacyclononane) in combination with glyoxylic acid methylester methyl hemiacetal (GMHA) results in a highly active and hydrogenperoxideefficientcatalyst for the epoxidation of olefins as well as the first homogeneous catalytic cis-dihydroxylation system with H2O2 and with turnover numbers up to 420.
[Mn 2 O 3(tmtacn)2 ](PF 6)2(tmtacn = 1,4,7-三甲基-1,4,7-三氮杂环壬烷)与乙醛酸甲酯甲基半缩醛(GMHA)结合使用会导致一种高活性和过氧化氢有效的催化剂,用于烯烃的环氧化,以及第一个均相催化的H 2 O 2顺式-二羟基化系统,其周转数最高为420。
A facile synthesis of vicinal cis-diols from olefins catalyzed by in situ generated Mn<sub>x</sub>O<sub>y</sub> nanoaggregates
作者:Diğdem Dalmizrak、Haydar Göksu、Mehmet Serdar Gültekin
DOI:10.1039/c5ra01646k
日期:——
The MnxOy oxide derivatives, mainly Mn3O4 nanoaggregates, were generated in situ by KMnO4/H2O2 during the synthesis of vicinal cis-diols from olefins.
from the results observed with strained and sterically hindered syn 1,2-diols, which undergo oxidative cleavage via a 12-I-5 spirobicyclic periodinane. The use of TFA, a protonating solvent, promotes the formation of the 12-I-5 intermediate for 1,2-diols of all types (sec,sec, sec,tert and tert,tert), leading to efficient oxidative fragmentation.