623-70-1Relevant articles and documents
Visible-Light-Promoted Intramolecular α-Allylation of Aldehydes in the Absence of Sacrificial Hydrogen Acceptors
Liu, Feng,Liu, Jia-Li,tu, Jia-Lin
supporting information, p. 7369 - 7372 (2020/10/05)
We report herein an unprecedented protocol for radical cyclization of aldehydes with pendant alkenes via synergistic photoredox, cobaloxime, and amine catalysis. The transformation was achieved in the absence of external oxidants, providing a variety of 5-, 6-, and 7-membered ring products with alkene transposition in satisfactory yields. The reaction exhibits wide functional group compatibility and occurs under mild conditions with extrusion of H2.
Fabrication of Ni3N nanorods anchored on N-doped carbon for selective semi-hydrogenation of alkynes
Shi, Xiaozhen,Wen, Xin,Nie, Shilin,Dong, Jie,Li, Jingde,Shi, Yongqing,Zhang, Huiling,Bai, Guoyi
, p. 22 - 30 (2019/12/26)
Nickel is a highly active catalyst for the semi-hydrogenation of alkynes. However, the low selectivity of the alkene product caused by the over-hydrogenation reaction on Ni has hindered its practical applications. In this work, we report a new nickel nitride (Ni3N)-catalyzed semi-hydrogenation of alkynes to the corresponding alkenes. The Ni3N nanorods were facilely fabricated via a direct pyrolysis of the solid mixture of nickel acetate tetrahydrate and melamine (Mlm). The Ni3N phase in the optimum catalyst (Ni3N/NC-6/5-550) is shown to be effective and stable in the semi-hydrogenation of alkynes, with a high yield and good selectivity for alkenes (Z/E ratios up to >99/1). Both terminal and internal alkynes bearing a broad scope of functional groups are readily converted into alkenes with good chemo- and stereoselectivity. Notably, it was found that the over-hydrogenation can be markedly suppressed even at high conversion of alkyne. Density functional theory (DFT) calculations reveal that the low interaction between the alkene product and the Ni3N might plays a critical role in the selectivity enhancement.
Copper-catalyzed, stereoconvergent,: Cis -diastereoselective borylative cyclization of ω -mesylate- α, β -unsaturated esters and ketones
Zuo, Ya-Jie,Chang, Xiao-Tong,Hao, Zhi-Ming,Zhong, Chong-Min
supporting information, p. 6323 - 6327 (2017/08/10)
The Cu(i)-catalyzed stereoconvergent borylative cyclization of ω-mesylate-α,β-unsaturated compounds is facilitated by a simple Cu-bisphosphine catalyst. This reaction provides a novel route to cis-β-boron-substituted five- and six-membered carbocycle and heterocycle esters. Mechanistic studies indicate that stereoconvergence and cis-substitution likely stem from the rapid enolation of the borylcopper adduct with the substrate double bond and the formation of a five-membered intermediate, respectively.
MONOMER, POLYMER, RESIST COMPOSITION, AND PATTERNING PROCESS
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, (2014/03/21)
A polymer comprising recurring units derived from a (meth)acrylate monomer of tertiary ester type having branched alkyl on alicycle is used to form a resist composition. When subjected to exposure, PEB and organic solvent development, the resist composition is improved in dissolution contrast.
Virtually complete E-selective α,β-unsaturated ester synthesis by Hg(OTf)2-catalyzed hydration of sec-ethoxyalkynyl acetate
Nishizawa, Mugio,Hirakawa, Hiroko,Nakagawa, Yuki,Yamamoto, Hirofumi,Namba, Kosuke,Imagawa, Hiroshi
, p. 5577 - 5580 (2008/09/17)
The reaction of alkyl-substituted sec-ethoxyalkynyl acetates with water catalyzed by Hg(OTf)2 afforded α,β-unsaturated esters in excellent yield with high catalytic turnover up to 1000 times under very mild reaction conditions with virtually complete E-selectivity, superior even to that of the HWE reaction.
Efficient large scale stereoinversion of (R)-ethyl 3-hydroxybutyrate
Carnell, Andrew J.,Head, Robert,Bassett, Derek,Schneider, Michael
, p. 821 - 825 (2007/10/03)
A three step method for the large scale preparation of enantiomerically pure ethyl (S)-3-hydroxybutyrate is reported starting from the commercial biopolymer poly[(R)-hydroxybutyrate]. The key step depends on the ability to cleanly invert the stereochemistry of (R)-ethyl 3-hydroxybutyrate via its mesylate ester under neutral conditions, avoiding the competing elimination process. This has been achieved in good (75%) yield on >100g scale by controlled addition of the mesylate to a stirred slurry of calcium carbonate in water at 80°C.
Reaction of silyl ketene acetals with epoxides: A new method for the synthesis of γ-butanolides
Maslak, Veselin,Matovi?, Radomir,Sai?i?, Radomir N.
, p. 8957 - 8966 (2007/10/03)
Titanium tetrachloride promoted reaction of silyl ketene acetals with epoxides, followed by acidic work-up, affords butanolides in moderate/good yields. With epihalohydrins the reaction is regioselective and occurs at the less substituted end of the epoxide; the γ-haloalkyl-γ-butanolides thus obtained can be further transformed into various products. Graphical Abstract
On the stereochemistry of β-elimination of β-silyl azides
Chabaud, Laurent,Landais, Yannick
, p. 6995 - 6998 (2007/10/03)
Fluoride-mediated elimination of syn and anti β-silyl azides was shown to afford the corresponding (Z)- and (E)-olefins, respectively, demonstrating that β-elimination of β-silyl azides is stereospecifically anti.
Indium-mediated reductive elimination of halohydrins
Cho, Sangwon,Kang, Soyeon,Keum, Gyochang,Kang, Soon Bang,Han, So-Yeop,Kim, Youseung
, p. 180 - 182 (2007/10/03)
Olefin formation has been successfully carried out by reductive elimination reactions of halohydrins with Pd(PPh3)4/In/InCl3 in aqueous media.
Esterification in dry media using ferric perchlorate adsorbed on silica gel
Parmar, Anupama,Kaur, Jatinder,Goyal, Rita,Kumar, Baldev,Kumar, Harish
, p. 2821 - 2826 (2007/10/03)
Adsorption of Fe(ClO4)3(H2O)6 onto chromatographic grade silica gel in the presence of alcohol ( to be used for esterification ) produces a supported reagent, Fe(ClO4)3(ROH)6/SiO2. This reagent, has been found effective for the rapid and high yield of esters, on grinding in the presence of carboxylic acids using pestle and mortar in the solid state.
