20780-49-8Relevant articles and documents
Iron Complex Catalyzed Selective C-H Bond Oxidation with Broad Substrate Scope
Jana, Sandipan,Ghosh, Munmun,Ambule, Mayur,Sen Gupta, Sayam
supporting information, p. 746 - 749 (2017/03/01)
The use of a peroxidase-mimicking Fe complex has been reported on the basis of the biuret-modified TAML macrocyclic ligand framework (Fe-bTAML) as a catalyst to perform selective oxidation of unactivated 3° C-H bonds and activated 2° C-H bonds with low catalyst loading (1 mol %) and high product yield (excellent mass balance) under near-neutral conditions and broad substrate scope (18 substrates which includes arenes, heteroaromatics, and polar functional groups). Aliphatic C-H oxidation of 3° and 2° sites of complex substrates was achieved with predictable selectivity using steric, electronic, and stereoelectronic rules that govern site selectivity, which included oxidation of (+)-artemisinin to (+)-10β-hydroxyartemisinin. Mechanistic studies indicate FeV(O) to be the active oxidant during these reactions.
Terpene Cyclizations inside a Supramolecular Catalyst: Leaving-Group-Controlled Product Selectivity and Mechanistic Studies
Zhang, Qi,Catti, Lorenzo,Pleiss, Jürgen,Tiefenbacher, Konrad
supporting information, p. 11482 - 11492 (2017/08/30)
The tail-to-head terpene cyclization is arguably one of the most complex reactions found in nature. The hydrogen-bond-based resorcinarene capsule represents the first man-made enzyme-like catalyst that is capable of catalyzing this reaction. Based on noncovalent interactions between the capsule and the substrate, the product selectivity can be tuned by using different leaving groups. A detailed mechanistic investigation was performed to elucidate the reaction mechanism. For the cyclization of geranyl acetate, it was found that the cleavage of the leaving group is the rate-determining step. Furthermore, the studies revealed that trace amounts of acid are required as cocatalyst. A series of control experiments demonstrate that a synergistic interplay between the supramolecular capsule and the acid traces is required for catalytic activity.
Visible-Light-Promoted Activation of Unactivated C(sp3)-H Bonds and Their Selective Trifluoromethylthiolation
Mukherjee, Satobhisha,Maji, Biplab,Tlahuext-Aca, Adrian,Glorius, Frank
supporting information, p. 16200 - 16203 (2016/12/27)
Selective functionalization of ubiquitous C(sp3)-H bonds using visible light is a highly challenging yet desirable goal in organic synthesis. The development of such processes relies on both rational design and serendipitous discoveries from innovative tools such as screening technologies. Applying a mechanism-based screening strategy, we herein report photoredox-mediated hydrogen atom transfer catalysis for the selective activation of otherwise unactivated C(sp3)-H bonds, followed by their trifluoromethylthiolation, which has high potential as a late-stage functionalization tool. The generality of this method is exhibited through incorporation of the trifluoromethylthio group in a large number of C(sp3)-H bonds with high selectivity without the need for an excess of valuable substrate.
Direct dehydrative esterification of alcohols and carboxylic acids with a macroporous polymeric acid catalyst
Minakawa, Maki,Baek, Heeyoel,Yamada, Yoichi M. A.,Han, Jin Wook,Uozumi, Yasuhiro
supporting information, p. 5798 - 5801 (2013/12/04)
A macroporous polymeric acid catalyst was prepared for the direct esterification of carboxylic acids and alcohols that proceeded at 50-80 C without removal of water to give the corresponding esters with high yield. Flow esterification for the synthesis of biodiesel fuel was also achieved by using a column-packed macroporous acid catalyst under mild conditions without removal of water.
Selective oxidation of unactivated C-H bonds by supramolecular control
Fung, Yat-Sing,Yan, Siu-Cheong,Wong, Man-Kin
experimental part, p. 3122 - 3130 (2012/05/07)
Efficient methods for dioxirane-based selective C-H bond oxidation by supramolecular control in H2O have been developed. With β-cyclodextrin as the supramolecular host, site-selective oxidation of the terminal over the internal tertiary C-H bond of 3,7-dimethyloctyl esters 3a-c was achieved. In addition, β-cyclodextrin selectively enhanced the C-H bond oxidation of cumene in a mixture of cumene and ethyl benzene in H2O. Through 1H NMR studies, the selectivity in C-H bond oxidation could be attributed to the inclusion complex formation between β-cyclodextrin and the substrates. The Royal Society of Chemistry 2012.
Indium triiodide catalysed one-step conversion of tetrahydropyranyl ethers to acetates with high selectivity
Ranu, Brindaban C.,Hajra, Alakananda
, p. 355 - 357 (2007/10/03)
Chemoselective one-step conversion of tetrahydropyranyl ethers of primary alcohols to corresponding acetates was carried out. The reaction occurred through an indium triiodide catalyzed transesterification process in ethyl acetate. The method provided advantages such as operational simplicity, acceptable reaction conditions to acid-sensitive functional groups and good yield.
Highly selective one-pot conversion of THP and MOM ethers to acetates by indium triiodide-catalysed deprotection and subsequent transesterification by ethyl acetate
Ranu, Brindaban C.,Hajra, Alakananda
, p. 2262 - 2265 (2007/10/03)
The chemoselective one-pot conversion of tetrahydropyranyl (THP) and methoxymethyl (MOM) ethers of primary alcohols to the corresponding acetates was presented. It was done using indium triiodide-catalysed deprotection and subsequent acetylation by ethyl acetate through a transesterification process. The advantages offered by the method included operational simplicity, 'green' methodology involving no toxic or hazardous chemicals and high yield.
SELECTIVE REDUCTION OF THE DISTANT DOUBLE BOND(S) IN GERANYL, FARNESYL AND GERANYL GERANYL DERIVATIVES.
Julia, Marc,Roy, Pierre
, p. 4991 - 5002 (2007/10/02)
Selective addition of hydrogen chloride on the non-proximal double bond(s) of the title compounds followed by hydrogenolysis led to selective hydrogenation of these double bond(s).
