5163-67-7Relevant articles and documents
On the stereoselection of iodolactonizations of 3-silyloxyalk-5-enoic acids
Bedford, Simon B.,Fenton, Garry,Knight, David W.,Shaw, Duncan E.
, p. 1505 - 1509 (1996)
Iodolactonizations of 3-triisopropylsilyloxyalk-5-enoic acids (10b and 12) proceed by way of common transition-state geometry 23, in which the silyloxy group is positioned axially, presumably due to hydrogen bonding with the carboxylic acid group.
Palladium-Catalyzed Low Pressure Carbonylation of Allylic Alcohols by Catalytic Anhydride Activation
Schelwies, Mathias,Paciello, Rocco,Pelzer, Ralf,Siegel, Wolfgang,Breuer, Michael
supporting information, p. 9263 - 9266 (2021/05/27)
A direct carbonylation of allylic alcohols has been realized for the first time with high catalyst activity at low pressure of CO (10 bar). The procedure is described in detail for the carbonylation of E-nerolidol, an important step in a new BASF-route to (?)-ambrox. Key to high activities in the allylic alcohol carbonylation is the finding that catalytic amounts of carboxylic anhydride activate the substrate and are constantly regenerated with carbon monoxide under the reaction conditions. The identified reaction conditions are transferrable to other substrates as well.
Enantioselective Alkylamination of Unactivated Alkenes under Copper Catalysis
Bai, Zibo,Zhang, Heng,Wang, Hao,Yu, Hanrui,Chen, Gong,He, Gang
supporting information, p. 1195 - 1202 (2021/02/05)
An enantioselective addition reaction of various alkyl groups to unactivated internal alkenes under Cu catalysis has been developed. The reaction uses amide-linked aminoquinoline as the directing group, 4-alkyl Hantzsch esters as the donor of alkyl radicals, and rarely used biaryl diphosphine oxide as a chiral ligand. β-lactams featuring two contiguous stereocenters at Cβ and the β substituent can be obtained in good yield with excellent enantioselectivity. Mechanistic studies indicate that a nucleophilic addition of the alkyl radical to CuII-coordinated alkene is the enantio-determining step.
Intramolecular Cyclization of Vinyldiazoacetates as a Versatile Route to Substituted Pyrazoles
Drikermann, Denis,G?rls, Helmar,Kerndl, Valerie,Vilotijevic, Ivan
supporting information, p. 1158 - 1162 (2020/07/20)
Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95percent. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- A nd tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents, this method constitutes a new entry to this valuable heterocyclic scaffold and may be of interest to all branches of the chemical industry.
PROCESS FOR THE PREPARATION OF UNSATURATED CARBOXYLIC ACIDS BY CARBONYLATION OF ALLYL ALCOHOLS AND THEIR ACYLATION PRODUCTS
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Paragraph 0231-0232, (2020/03/01)
The present invention relates to a process for carbonylating allyl alcohols at low temperature, low pressure and/or low catalyst loading. In an alternative embodiment, an acylation product of the allyl alcohol is used for the carbonylation. The present invention likewise relates to the preparation of conversion products of these carbonylation products and specifically of (?)-ambrox.
Direct Enantioselective and Regioselective Alkylation of β,γ-Unsaturated Carboxylic Acids with Chiral Lithium Amides as Traceless Auxiliaries
Yu, Kai,Miao, Bukeyan,Wang, Wenqi,Zakarian, Armen
supporting information, (2019/03/19)
Efficient asymmetric alkylation of β,γ-unsaturated carboxylic acids without prior functionalization is enabled by chiral lithium amides. Enantioselectivity is imparted by a putative mixed lithium amide-enediolate aggregate that acts a traceless auxiliary formed in situ, allowing for a direct asymmetric alkylation and a simple recovery of the chiral reagent.
Structure-Odor Relationships of (Z)-3-Alken-1-ols, (Z)-3-Alkenals, and (Z)-3-Alkenoic Acids
Lorber, Katja,Zeh, Gina,Regler, Johanna,Buettner, Andrea
, p. 2334 - 2343 (2018/03/21)
(Z)-3-Unsaturated volatile acids, alcohols, and aldehydes are commonly found in foods and other natural sources, playing a vital role in the attractiveness of foods but also as compounds with chemocommunicative function in entomology. However, a systematic investigation of their smell properties, especially regarding humans, has not been carried out until today. To close this gap, the odor thresholds in air and odor qualities of homologous series of (Z)-3-alken-1-ols, (Z)-3-alkenals, and (Z)-3-alkenoic acids were determined by gas chromatography-olfactometry. It was found that the odor qualities in the series of the (Z)-3-alken-1-ols and (Z)-3-alkenals changed, with increasing chain length, from grassy, green to an overall fatty and citrus-like, soapy character. On the other hand, the odor qualities of the (Z)-3-alkenoic acids changed successively from cheesy, sweaty via plastic-like, to waxy in their homologous series. With regard to their odor potencies, the lowest thresholds in air were found for (Z)-3-hexenal, (Z)-3-octenoic acid, and (Z)-3-octenal.
Rh2(R -TPCP)4-catalyzed enantioselective [3+2]-cycloaddition between nitrones and vinyldiazoacetates
Qin, Changming,Davies, Huw M. L.
supporting information, p. 14516 - 14519 (2013/10/22)
Rhodium-catalyzed reaction of vinyldiazoacetates with nitrones results in a formal [3+2]-cycloaddition to generate 2,5-dihydroisoxazoles with high levels of asymmetric induction. The cascade reaction begins with a vinylogous addition event, followed by an iminium addition ring-closure/hydride migration/alkene isomerization cascade. Dirhodium tetrakis(triarylcyclopropanecarboxylates) are the optimum catalysts for this process.
Enantiodivergent and γ-selective asymmetric allylic amination
Wang, Jianmin,Chen, Jie,Kee, Choon Wee,Tan, Choon-Hong
, p. 2382 - 2386 (2012/05/19)
Double agent: The title reaction using the guanidine catalyst 1 can deliver both enantiomers of the product with excellent enantioselectivity by judicious choice of the double bond geometry of the the β,γ-unsaturated carbonyl compound. Computational studies reveal the possible origin of the inversed enantioselectivity, and the potential for enantiodivergent synthesis chiral amine-containing substrates is attractive. Copyright
Combined transition-metal- and organocatalysis: An atom economic C3 homologation of alkenes to carbonyl and carboxylic compounds
Kemme, Susanne T.,Smejkal, Tomas,Breit, Bernhard
supporting information; experimental part, p. 3423 - 3433 (2010/06/21)
A combination of regioselective room-temperature/ambient-pressure hydroformylation (transitionmetal catalysis) and decarboxylative Knoevenagel reactions (organocatalysis) allowed for the development of an efficient, one-pot C3 homologation of terminal alkenes to (E)-α,β-unsaturated acids and esters, (E)-β,γ-unsaturated acids, (E)-α-cyano acrylic acids, and α,β-unsaturated nitriles. All reactions proceed under mild conditions, tolerate a variety of functional groups, and furnish unsaturated carbonyl compounds in good yields and with excellent regioand stereocontrol. Further, an iterative C2 homologation of (E)-α,β-unsaturated carboxylic acids is possible through a combination of decarboxylative hydroformylation employing a supramolecular catalyst followed by decarboxylative Knoevenagel condensation with an organocatalyst.
