- Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
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The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
- Dong, Guangbin,Xu, Yan,Zhou, Xukai
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supporting information
p. 20042 - 20048
(2021/12/03)
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- Platinum-catalyzed α,β-unsaturated carbene formation in the formal syntheses of frondosin B and liphagal
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Formal syntheses of tetracyclic terpenoids frondosin B and liphagal are described. Both synthetic routes rely on the use of platinum-catalyzed α,β-unsaturated carbene formation for the key C-C bond forming transformations. The successful route toward frondosin B utilizes a formal (4 + 3) cycloaddition, while the liphagal synthesis features the vinylogous addition of an enol nucleophile as a key step. Both synthetic routes are discussed, revealing insights into structural requirements in the catalytic a,β-unsaturated carbene reaction manifold.
- Huynh, Khoi Q.,Seizert, Curtis A.,Ozumerzifon, Tarik J.,Allegretti, Paul A.,Ferreira, Eric M.
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supporting information
p. 294 - 297
(2017/11/28)
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- Synthesis of three putative kairomones of the beech leaf-mining weevil Orchestes fagi (L.)
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The beech leaf-mining weevil, Orchestes fagi (L.), also known as the beech flea weevil, is a common and widespread pest of beech, Fagus sylvatica L., in its native Europe. It now appears to be well established in Nova Scotia, Canada. We report a novel synthesis of 9-geranyl-p-cymene and syntheses of 9-geranyl-α-terpinene and 1,1-dimethyl-3-methylene-2-vinylcyclohexane, making partial use of known methods. All three of these compounds are found in beech leaf volatiles and/or wood and are putative kairomones of the beech leaf-mining weevil.
- Mayo,Silk,Abeysekera,MaGee
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supporting information
p. 1124 - 1132
(2016/07/21)
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- A novel, facile approach to frondosin B and 5-epi-liphagal via a new [4 + 3]-cycloaddition
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A new [4 + 3]-cycloaddition between benzofuran allylic alcohols and dienes, promoted by camphorsulfonic acid, has been identified. A novel strategy which used this cycloaddition as a key step has been developed for the synthesis of 6,7,5-tricyclic skeleta
- Zhang, Jie,Li, Liqi,Wang, Yongxiang,Wang, Wenjing,Xue, Jijun,Li, Ying
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supporting information
p. 4528 - 4530
(2012/11/07)
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- Scope and mechanism of the (4+3) cycloaddition reaction of furfuryl cations
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It all adds up: Furfuryl alcohols are revealed as direct reaction partners for a wide range of conjugated dienes in a (4+3) cycloaddition motif (see scheme). This novel Lewis acid promoted process gives straightforward access to various polycyclic skeletons containing a seven-membered ring. A plausible cationic stepwise mechanism was confirmed by DFT calculations. Copyright
- Winne, Johan M.,Catak, Saron,Waroquier, Michel,Van Speybroeck, Veronique
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supporting information; experimental part
p. 11990 - 11993
(2012/02/14)
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- THERAPEUTIC AGENT
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The present invention relates to a therapeutic agent or prophylactic agent for a disease accompanying an abnormality in an amount of insulin or insulin response, an insulin-mimetic action agent, a food, beverage, or feed, an agent for enhancement of gluco
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Page/Page column 21-22
(2008/06/13)
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- The Diels-Alder Route to Drimane related Sesquiterpenes; Synthesis of Cinnamolide, Polygodial, Isodrimeninol, Drimenin and Warburganal
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The stereospecific preparation of various 1-vinyl-2,6,6-trimethylcyclohex-1-enes (6) as potential diene precursors in the Diels-Alder reaction with dimethyl acetylenedicarboxylate have been investigated.The reaction of the parent diene (6a) with dimethyl acetylenedicarboxylate affords an adduct (18) in 94percent yield.This species was reductively isomerised using 10percent Pd/C/H2 and a mineral acid to give a trans-fused decalin diester (19).Reduction of (19) with lithium aluminium hydride afforded 1,4,4a,5,6,8,8a-octahydro-5,8,8a-trimethyl-1β,4aα,8aβ-naphthalene-1,2-dimethanol (24) a key starting material for the highly efficient syntheses of five drimane sesquiterpene natural products, cinnamolide (1), polygodial (2), isodrimeninol (3), drimenin (4), and warbuganal (5).Microbial oxidation reactions using C. elegans or A. niger of (2), (24), and (1) gave good yields of the corresponding 3β-hydroxy derivatives, (30), (31), and (32).Several other unusually substituted drimane derivatives are reported.
- Hollinshead, David M.,Howell, S. Christopher,Ley, Steven V.,Mahon, Michael,Ratcliffe, Norman M.,Worthington, Paul A.
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p. 1579 - 1589
(2007/10/02)
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- Synthesis of Cinnamolide and Polygodial
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Starting from 2,6,6-trimethyl-1-vinylcyclohex-1-ene a short synthesis of the sesquiterpenes cinnamolide and polygodial has been achieved with 60 percent and 57 percent overall yields, respectively.
- Howell, S. Christopher,Ley, Steven V.,Mahon, Michael,Worthington, Paul A.
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p. 507 - 508
(2007/10/02)
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