The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Yoshihiro Sato - One of the best experts on this subject based on the ideXlab platform.
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rhodium i catalyzed cyclization of allenynes with a Carbonyl Group through unusual insertion of a co bond into a rhodacycle intermediate
Angewandte Chemie, 2014Co-Authors: Yoshihiro Oonishi, Takayuki Yokoe, Akihito Hosotani, Yoshihiro SatoAbstract:Rhodium(I)-catalyzed cyclization of allenynes with a tethered Carbonyl Group was investigated. An unusual insertion of a CO bond into the C(sp2)–rhodium bond of a rhodacycle intermediate occurs via a highly strained transition state. Direct reductive elimination from the obtained rhodacyle intermediate proceeds to give a tricyclic product containing an 8-oxabicyclo[3.2.1]octane skeleton, while β-hydride elimination from the same intermediate gives products that contain fused five- and seven-membered rings in high yields.
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further studies on nickel promoted or catalyzed cyclization of 1 3 diene and a tethered Carbonyl Group
Journal of the American Chemical Society, 2000Co-Authors: Yoshihiro Sato, And Masanori Takimoto, Miwako MoriAbstract:A nickel-promoted intramolecular cyclization of 1,3-diene with the tethered Carbonyl Group was developed using the catalyst generated by reduction of Ni(acac)2 with DIBAL-H in the presence of PPh3. It was found that the addition of 1,3-CHD to the reaction mixture affected the regiochemistry of olefin on the side chain of the cyclized product. The reaction course of this cyclization can be accounted for by two possible mechanisms. In one mechanism, a nickel hydride complex plays a key role and the cyclization proceeds via π-allylnickel intermediate. In the other mechanism, a zero-valent nickel complex is the active species and the cyclization proceeds via nickelacycle intermediates. These mechanistic considerations led to finding two nickel(0)-catalyzed cyclizations of 1,3-diene and the tethered aldehyde, in which the five- to seven-membered ring products were produced in a regio- and stereoselective manner via π-allylnickel intermediate or via a transmetalation process of nickelacycle intermediates with i...
Akhila K Sahoo - One of the best experts on this subject based on the ideXlab platform.
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gold catalyzed regioselective hydration of propargyl acetates assisted by a neighboring Carbonyl Group access to α acyloxy methyl ketones and synthesis of actinopolymorphol b
Journal of Organic Chemistry, 2011Co-Authors: Nayan Ghosh, Sanatan Nayak, Akhila K SahooAbstract:A general atom-economical approach for the synthesis of α-acyloxy methyl ketone is demonstrated through regioselective hydration of a wide range of propargyl acetates. Readily available catalyst comprising of 1% Ph3PAuCl and 1% AgSbF6 in dioxane−H2O efficiently hydrolyzes the terminal alkynes of the propargyl acetate in the absence of acid promoters at ambient temperature within a short time. Effective regioselective hydration is facilitated by the neighboring Carbonyl Group as demonstrated through 18O-labeling study. Compatibility of functional moieties and tolerance to various acid-labile protecting Groups are observed. The catalytic condition is also suitable to perform hydration of TMS-substituted propargyl acetates, even though it requires prolonged reaction time for completion. Stereointegrity of the propargylic acetate is preserved during the hydration. The robustness of the system is successfully demonstrated through gram scale preparation of the product in nearly quantitative yield. The common α-...
Jack Hamelin - One of the best experts on this subject based on the ideXlab platform.
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solvent free protection of Carbonyl Group under microwave irradiation
Tetrahedron Letters, 1997Co-Authors: Bertrand Perio, M J Dozias, Patrick Jacquault, Jack HamelinAbstract:Abstract Protection of aldehydes and ketones as acetals or dioxolanes catalysed by PTSA or KSF clay was readily achieved from orthoformates, 1,2-ethanediol or 2,2-dimethyl-1,3-dioxolane without solvent under microwave irradiation.
Miwako Mori - One of the best experts on this subject based on the ideXlab platform.
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further studies on nickel promoted or catalyzed cyclization of 1 3 diene and a tethered Carbonyl Group
Journal of the American Chemical Society, 2000Co-Authors: Yoshihiro Sato, And Masanori Takimoto, Miwako MoriAbstract:A nickel-promoted intramolecular cyclization of 1,3-diene with the tethered Carbonyl Group was developed using the catalyst generated by reduction of Ni(acac)2 with DIBAL-H in the presence of PPh3. It was found that the addition of 1,3-CHD to the reaction mixture affected the regiochemistry of olefin on the side chain of the cyclized product. The reaction course of this cyclization can be accounted for by two possible mechanisms. In one mechanism, a nickel hydride complex plays a key role and the cyclization proceeds via π-allylnickel intermediate. In the other mechanism, a zero-valent nickel complex is the active species and the cyclization proceeds via nickelacycle intermediates. These mechanistic considerations led to finding two nickel(0)-catalyzed cyclizations of 1,3-diene and the tethered aldehyde, in which the five- to seven-membered ring products were produced in a regio- and stereoselective manner via π-allylnickel intermediate or via a transmetalation process of nickelacycle intermediates with i...
Chuanying Li - One of the best experts on this subject based on the ideXlab platform.
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rhodium catalyzed synthesis of multi substituted furans from n sulfonyl 1 2 3 triazoles bearing a tethered Carbonyl Group
Organic chemistry frontiers, 2015Co-Authors: Wenbiao Zhang, Chuanying LiAbstract:The efficient synthesis of highly functionalized furan derivatives from 1-sulfonyl-1,2,3-triazoles with a pendent Carbonyl Group is reported. The process involves an intramolecular trapping of α-imino carbene and subsequent aromatization.