6864-62-6Relevant academic research and scientific papers
Visible-light-driven radical 1,3-addition of selenosulfonates to vinyldiazo compounds
Li, Weiyu,Zhou, Lei
supporting information, p. 6652 - 6658 (2021/09/10)
Herein, we report a visible-light-driven radical 1,3-selenosulfonylation of vinyldiazo compounds with selenosulfonates, providing various γ-seleno allylic sulfones in good yields. This photochemical reaction was carried out at room temperature in an open flask using ethyl acetate as the solvent without any photocatalysts or additives. The control experiments corroborated that the 1,3-addition proceeded via a radical-chain propagation process. The synthetic applications of the resulting products were demonstrated by deselenization, reduction, bromination and allylation.
N, N’-dimethyl formamide (DMF) mediated Vilsmeier–Haack adducts with 1,3,5-triazine compounds as efficient catalysts for the transesterification of β-ketoesters
Chityala, Yadaiah,Duguta, Govardhan,Kamatala, Chinna Rajanna,Muddam, Bhooshan,Mukka, Satish Kumar
supporting information, p. 1641 - 1655 (2020/05/25)
N, N’-dimethyl formamide (DMF) mediated Vilsmeier–Haack (VH) adducts with 1,3,5-triazine compunds such as trichloroisocyanuric acid (TCCA) and trichlorotriazine (TCTA) were prepared by replacing classical oxy chlorides POCl3, and SOCl2, which were explored as efficient catalysts for the transesterification of β-ketoesters. The prepared (TCCA/DMF) and (TCTA/DMF) adducts improved greenery of the classical Vilsmeier–Haack reagents (POCl3/DMF), and (SOCl2/DMF), and demonstrated their better efficient catalytic ativity. Reaction times were in the range: 3.5 to 6.5 hr (SOCl2/DMF); 2.8–5.2 hr (POCl3/DMF); 2.5–5.2 hr (TCCA/DMF) and 2.5–5.0 hr (TCTA/DMF) catalytic systems. Ultrasonically (US) assisted protocols with these reagents further reduced the reaction times (two to three times), while microwave assisted (MW) protocols with these reagents were much more effective. The reactions could be completed in only few seconds (less than a minute) in MWassisted protocols as compared to US assited reactions, followed by good product yields.
Regioselective Rhodium-Catalyzed Addition of β-Keto Esters, β-Keto Amides, and 1,3-Diketones to Internal Alkynes
Beck, Thorsten M.,Breit, Bernhard
supporting information, p. 5839 - 5844 (2016/12/18)
The first rhodium-catalyzed regioselective addition of 1,3-dicarbonyl compounds, including β-keto esters, β-keto amides, and 1,3-diketones, to internal alkynes furnishes branched allylic compounds. By applying RhI/DPEphos/TFA as the catalytic system, aliphatic as well as aromatic internal methyl-substituted alkynes act as suitable substrates to yield valuable branched α-allylated 1,3-dicarbonyl compounds regioselectively in good to excellent yields. A simple basic saponification–decarboxylation procedure provides access to valuable γ,δ-unsaturated ketones. The reaction shows a broad functional-group tolerance, and numerous structural variations on both reaction partners highlight the synthetic potential and flexibility of this method.
A chemoselective route to β-enamino esters and thioesters
Xin, Dongyue,Burgess, Kevin
supporting information, p. 2108 - 2110 (2014/05/06)
Conditions were developed for syntheses of β-enamino esters, thioesters, and amides. These reactions involve hydroxybenzotriazole derivatives in buffered media. Illustrative syntheses of some heterocyclic systems are given, including some related to protein-protein interface mimics.
Prussian blue as an efficient catalyst for rate accelerations in the transesterification of β-ketoesters
Srinivas,Rajanna,Krishnaiah,Kumar, M. Satish,Reddy, J. Narender
, p. 1212 - 1220 (2014/04/17)
Prussian blue triggered transesterification of ethylacetoacetate with various alcohols underwent efficiently. The reaction is mild, eco-friendly, and selective with good yields. The proposed reaction pathway depicts the formation of an intermediate by the interaction of β-ketoesters with catalytic site of the Prussian blue, followed by nucleophilic attack of the alcohol at the electrophilic center followed by successive elimination of the proton to give the product. Observed longer reaction times under conventional conditions reduced amazingly under sonication and microwave irradiation followed enhanced yield of products.
Regio- and diastereoselective crotylboration of vic-tricarbonyl compounds
Rossbach, Jan,Baumeister, Julia,Harms, Klaus,Koert, Ulrich
supporting information, p. 662 - 665 (2013/03/13)
Crotylboration of vic-diketoamides and vic-diketo esters was achieved with high diastereoselectivity and complementary regioselectivity. Whereas (E)-crotylboration of α,β-diketoamides resulted in high yields (91-99 %) of β-crotylated products obtained as a single diastereomer (anti), Lewis acid promoted crotylboration of α,β-diketo esters yielded the α-crotylated species with the anti product as main diastereomer. (E)-Crotylboration of α,β-diketoamides resulted in high yields (91-99 %) of β-crotylated products obtained as a single diastereomer (anti). Lewis acid promoted crotylboration of α,β-diketo esters yielded the α-crotylated species with the anti product as main diastereomer. Copyright
Manganese(II) salts as efficient catalysts for chemo selective transesterification of β-keto esters under non-conventional conditions
Krishnaiah,Sandeep,Kondhare,Rajanna,Narendar Reddy,Rajeshwar Rao,Zhubaidha
, p. 703 - 706 (2013/02/23)
Transesterification of β-ketoesters with various alcohols has been studied under conventional and non-conventional conditions using desktop chemicals such as Mn(II) salts as catalysts. These methods offered transesterification of β-ketoesters in good yields with dramatic rate accelerations and reduced reaction times. The developed protocols under nonconventional methods such as sonication and microwave irradiation are highly promising compared with the existing procedures.
Selective Catalytic Transesterification, Transthiolesterification, and Protection of Carbonyl Compounds over Natural Kaolinitic Clay
Ponde, Datta E.,Deshpande, Vishnu H.,Bulbule, Vivek J.,Sudalai, Ammugam,Gajare, Anil S.
, p. 1058 - 1063 (2007/10/03)
Transesterification and transthiolesterification of β-keto esters with variety of alcohols and thiols and selective protection of carbonyl functions with various protecting groups catalyzed by natural kaolinitic clay are described. The clay has been found to be an efficient catalyst in transesterifying long chain alcohols, unsaturated alcohols, and phenols to give their corresponding β-keto esters in high yields. For the first time, transthiolesterification of β-keto esters with a variety of thiols has been achieved under catalytic conditions. Clay also catalyzes selective transesterification of β-keto esters by primary alcohols in the presence of secondary and tertiary alcohols giving corresponding β-keto esters. A systematic study involving the reactivity of different nucleophiles (alcohols, amines, and thiols) toward β-keto esters is also described. Sterically hindered carbonyl groups as well as α,β-unsaturated carbonyl groups underwent protection without the deconjugation of the double bond. Chemoselective protection of aldehydes in the presence of ketones has also been achieved over natural kaolinitic clay.
Transacetoacetylation with tert-Butyl Acetoacetate: Synthetic Apllications
Witzeman, J. Stewart,Nottingham, W. Dell
, p. 1713 - 1718 (2007/10/02)
Reaction of various nucleophiles with tert-butyl acetoacetate (t-BAA, 1a) is shown to be a convenient method for the preparation of a wide variety of acetoacetic acid derivatives.This material can be used to prepare acetoacetates and acetoacetamides from a wide variety of alcohols and amines.Reaction of 1a with an unhindered primary amine such as n-heptylamine under standard conditions gives unwanted byproducts due to the formation of the enamines 24 and 25.Formation of these byproducts can be minimized by dilution and/or altering the mode of addition.
Kinetic and Spectroscopic Studies on the Thermal Decomposition of 2,2,6-Trimethyl-4H-1,3-dioxin-4-one: Generation of Acetylketene
Clemens, Robert J.,Witzeman, Stewart J.
, p. 2186 - 2193 (2007/10/02)
Acetylketene is shown to be a reactive intermediate in thermolytic reactions of 2,2,6-trimethyl-4H-1,3-dioxin-4-one (the diketene-acetone adduct) via a series of kinetic studies.The uncatalyzed acetoacetylations of phenol, 1-butanol, and di-n-butylamine with the title dioxinone at 82-107 deg C are first-order reactions in which the rate-limiting step is the formation of acetylketene and acetone, presumably via a retro-Diels-Alder reaction.Isopropenyl acetoacetate is not an intermediate in the aforementioned reactions but also provides acetylketene when heated.Acetylketene was observed by FT-IR spectroscopy in an argon matrix.
