- One-pot enol silane formation-Mukaiyama aldol reactions: Crossed aldehyde-aldehyde coupling, thioester substrates, and reactions in ester solvents
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Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and a trialkylamine base promote both in situ enol silane/silyl ketene acetal formation and Mukaiyama aldol addition reactions between a variety of reaction partners in a single reaction flask. Isolation of the required enol silane or silyl ketene acetal is not necessary. For example, crossed aldol reactions between α-disubstituted aldehydes and non-enolizable aldehydes yield β-hydroxy aldehydes in good yield. In a related reaction, the common laboratory solvent ethyl acetate functions as both an enolate precursor and a green reaction solvent. When thioesters are employed as enolate precursors, high yields for additions to non-enolizable aldehydes are routinely observed.
- Downey, C. Wade,Dixon, Grant J.,Ingersoll, Jared A.,Fuller, Claire N.,MacCormac, Kenneth W.,Takashima, Anna,Sediqui, Rohina
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supporting information
(2019/10/14)
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- Enantioselective total synthesis of (-)-acylfulvene and (-)-irofulven
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(Chemical Equation Presented) We report our full account of the enantioselective total synthesis of (-)-acylfulvene (1) and (-)-irofulven (2), which features metathesis reactions for the rapid assembly of the molecular framework of these antitumor agents. We discuss (1) the application of an Evans Cu-catalyzed aldol addition reaction using a strained cyclopropyl ketenethioacetal, (2) an efficient enyne ring-closing metathesis cascade reaction in a challenging setting, (3) the reagent IPNBSH for a late-stage reductive allylic transposition reaction, and (4) the final RCM/dehydrogenation sequence for the formation of (-)-acylfulvene (1) and (-)-irofulven (2).
- Siegel, Dustin S.,Piizzi, Grazia,Piersanti, Giovanni,Movassaghi, Mohammad
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scheme or table
p. 9292 - 9304
(2010/03/04)
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- Potent, selective, orally bioavailable inhibitors of tumor necrosis factor-α converting enzyme (TACE): Discovery of indole, benzofuran, imidazopyridine and pyrazolopyridine P1′ substituents
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Potent and selective inhibitors of tumor necrosis factor-α converting enzyme (TACE) were discovered with several new heterocyclic P1′ groups in conjunction with cyclic β-amino hydroxamic acid scaffolds. Among them, the pyrazolopyridine provided the best o
- Lu, Zhonghui,Ott, Gregory R.,Anand, Rajan,Liu, Rui-Qin,Covington, Maryanne B.,Vaddi, Krishna,Qian, Mingxin,Newton, Robert C.,Christ, David D.,Trzaskos, James,Duan, James J.-W.
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p. 1958 - 1962
(2008/12/20)
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- The tandem intermolecular Paterno-Buechi reaction: Formation of tetrahydrooxepins
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The Paterno-Buechi reaction is the [2 + 2] photocycloaddition between carbonyl compounds and electron rich alkenes to generate oxetane products. By the introduction of substituted cyclopropyl rings to the alkene components, the utility of this reaction has been extended to facilitate the synthesis of substituted tetrahydrooxepins. It is proposed that initial addition of oxygen radicals to cyclopropyl enol ethers generates cyclopropylmethyl radicals which, when the cyclopropane ring bears appropriate radical-stabilising groups (e.g. phenyl, CO2Et), undergo rapid fragmentation to form homoallylic 1,7-biradicals which then recombine to deliver the observed tetrahydrooxepin products. The importance of various radical-stabilising substituents on the efficiency of tetrahydrooxepin formation is examined.
- Gan, Chee Yong,Lambert, John N.
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p. 2363 - 2372
(2007/10/03)
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- IMPROVED PREPARATION OF BICYCLOPROPYLIDENE
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A reproducible synthesis of the title compound 6 in 10 - 20 g quantities is reported.The use of a polymeric base such as (diethylaminomethyl)-polystyrene is exemplified in the transformation of a sensitive alcohol 4 into a labile chloride 5.
- Weber, Walter,Meijere, Armin de
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p. 837 - 846
(2007/10/02)
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