5009-32-5Relevant academic research and scientific papers
Asymmetric synthesis of the constitutive C22-carboxylic acid of macroviracin A
Kanojia, Seema V.,Chatterjee, Sucheta,Gamre, Sunita,Chattopadhyay, Subrata,Sharma, Anubha
, p. 1732 - 1738 (2015)
An efficient asymmetric synthesis of the C22-trihydroxy fatty acid component of macroviracin A has been developed. The key steps were highly enantioselective (i) lipase-catalyzed acylation, (ii) InCl3-(S)-BINOL mediated allylation, and (iii) asymmetric dihydroxylation (ADH) reaction. The moderate diastereoselectivity of the ADH reaction was overridden by converting the resultant diol diastereomers to the required epoxide enantiomer.
METHOD FOR CONVERTING HYDROXYL GROUP OF ALCOHOL
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Paragraph 0497-0498, (2021/02/19)
The present invention relates to: a method for converting a hydroxyl group of an alcohol; and a catalyst which makes the method possible. A method for converting a hydroxyl group of an alcohol according to the present invention is characterized by producing a compound represented by CH(R1)(R2)Nu (wherein R1, R2 and Nu are as defined below) by reacting an alcohol represented by CH(R1)(R2)OH (wherein each of R1 and R2 represents a hydrogen atom, an optionally substituted alkyl group, or the like) and a compound having an active proton, which is represented by H-Nu (wherein Nu represents a group represented by —CHX1-EWG1 or —NR3R4; X1 represents a hydrogen atom or the like; EWG1 represents an electron-withdrawing group; and each of R3 and R4 represents a hydrogen atom, an optionally substituted alkyl group, or the like), with each other in the presence of a complex of a group 7-11 metal of the periodic table and at least one solid base that is selected from the group consisting of layered double hydroxides, composite oxides and calcium hydroxide.
Highly productive α-alkylation of ketones with alcohols mediated by an Ir-oxalamidato/solid base catalyst system
Maeda, Hironori,Nara, Hideki,Shimizu, Hideo
supporting information, p. 2772 - 2779 (2020/12/29)
An Ir-oxalamidato complex in combination with a solid base (e.g., magnesium aluminometasilicate/Ca(OH)2) significantly improved the catalyst productivity in α-alkylation of methyl ketones with primary alcohols. Optimization through systematic variation of the oxalamidato ligand led to a practical turnover number (TON) of 10 000.40 000.
Dendrimer-Palladium complex catalyzed oxidation of terminal alkenes to methyl ketones
Zweni, Pumza P.,Alper, Howard
, p. 849 - 854 (2007/10/03)
Silica-supported polyamidoamine (PAMAM) dendrimers with different spacer lengths were prepared. After the introduction of diphenylphosphino groups, complexation to dibenzylidenepalladium(0) gave the desired silica-supported dendrimer - palladium catalyst complexes G0 to G4-C2-Pd. These catalysts showed activity towards the oxidation of terminal alkenes to methyl ketones. A dependence of catalytic activity on the spacer length of the diamine in PAMAM was observed.
Highly efficient amphiphilic cleavage of γ-iodo carbonyl substrates with aluminum tris(2,6-diphenylphenoxide)/t-BuLi system
Kondo, Yuichiro,Kon-i, Kana,Ooi, Takashi,Maruoka, Keiji
, p. 9041 - 9044 (2007/10/03)
A conceptually new amphiphilic cleavage of the αβ C-C bonds of γ-iodo carbonyl substrates has been realized by the effective use of a combined Lewis acid/base system consisting of aluminum tris(2,6-diphenylphenoxide) (ATPH)/t-BuLi. This new amphiphilic bond cleavage reaction can be applied to a wide variety of γ-iodo carbonyl substrates and therefore serves as a highly efficient and general route to both cyclic and acyclic unsaturated carbonyl compounds.
Designing photosystems for harvesting photons into electrons by sequential electron-transfer processes: Reversing the reactivity profiles of α,β-unsaturated ketones as carbon radical precursor by one electron reductive β-activation
Pandey, Ganesh,Hajra, Saumen,Ghorai, Manas K.,Kumar, K. Ravi
, p. 8777 - 8787 (2007/10/03)
Two photosystems are developed to harvest visible-light photons into electrons via sequential electron transfer processes. Photosystem-A (PS-A) consisted of DCA as light harvesting electron acceptor and Ph3P as sacrificial electron donor, whereas photosystem-B (PS-B) employed DCA as usual electron acceptor, DMN as a primary electron donor, and ascorbic acid as a secondary and sacrificial electron donor. α,β-Unsaturated ketones are utilized as secondary electron accepters. The design of these photosystems is based on the thermodynamic feasibility of electron transfer between each participating components. Electron transfer from DCA.- to α,β-unsaturated ketones leads to their β-activation as carbon centered radicals which cyclizes efficiently to tethered activated olefins. Cyclization with a nonactivated olefin is found to be moderate. The cyclization stereochemistries have been illustrated by studying the PET activation of 5 and 21. The exclusive trans-stereochemistry observed in 8 is explained by considering the thermodynamic equilibration of initially formed syn-intermediate 10 from 5. The isolation of trace amount of 9 in this reaction substantiates the syn-intermediacy as primary intermediate which is further confirmed by the isolation of 25 from 21. Formation of 25 suggests that wherever the syn-intermediate is thermodynamically more stable, it invariably undergoes further cyclization to geometrically well-placed enolate double bond. An interesting observation is made by isolating 9 as a major product from the PET activation of 5 using PS-B. Stabilization of 10 by ascorbic acid is suggested to be the plausible explanation for this unusual observation. Radicals produced by the reductive β-activation of α,β-unsaturated ketones follow well established radical cyclization rules which is exemplified by studying the reactions of 39 and 40. Generality of these cyclizations is demonstrated from the PET reactions of 29-32. Synthesis of 49, an important structural framework of biologically active angularly fused triquinanes, from 48 is included in this study to demonstrate the varied applicability of this strategy.
Visible light initiated photosensitised electron transfer (PET) reductive β-activation of α, β-unsaturated ketones for radical cyclisation: A new concept in promoting radical reactions
Pandey, Ganesh,Hajra, Saumen,Ghorai, Manas K.
, p. 7837 - 7840 (2007/10/02)
Photosensitised one electron reductive β-activation of α,β-unsaturated ketones for radical cyclisations are reported.
Direct Formation and Subsequent Substitution of Remote Ketone-Functionalized Organocopper Reagents
Ebert, Greg W.,Klein, Walter R.
, p. 4744 - 4747 (2007/10/02)
Remote ketone-functionalized aryl- and alkylcopper reagents have been synthesized by the use of a highly activated form of zero-valent copper. 5-Bromo-2-pentanone and 4-iodobenzophenone undergo oxidative addition with activated copper to form 5-cuprio-2-pentanone and 4-cupriobenzophenone, respectively.These, in turn, can be cross-coupled with alkyl halides to produce the corresponding alkylated ketones and with acid chlorides to form the corresponding diketones.By use of this methodology, a two-step, one-pot synthesis of methyl (E)-9-oxo-2-decenoate and 8-nonen-2-one have been achieved.The former compound is the methyl ester of the "queen substance" of the honey bee, and the latter is part of an "attractant mixture" for cheese mites found in cheddar cheese.These syntheses were accomplished by converting commercially available 6-bromo-2-hexanone to 6-cuprio-2-hexanone followed by cross-coupling with commercially available methyl 4-bromocrotonate and allyl bromide, respectively.
