- Selective Cascade Reaction of Bisallenes via Palladium-Catalyzed Aerobic Oxidative Carbocyclization–Borylation and Aldehyde Trapping
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A cascade reaction, consisting of a palladium-catalyzed regioselective aerobic oxidative carbocyclization–borylation of bisallenes and a final aldehyde trapping, afforded triene alcohols with high diastereoselectivity. The cascade reaction occurs under mild reaction conditions and proceeds via an allylboron intermediate that is trapped by the aldehyde in a stereoselective manner.
- Naidu, Veluru Ramesh,Posevins, Daniels,Volla, Chandra M. R.,B?ckvall, Jan-E.
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- Synthesis of Cross-Conjugated Polyenes via Palladium-Catalyzed Oxidative C-C Bond Forming Cascade Reactions of Allenes
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An efficient palladium-catalyzed oxidative C-C bond forming cascade reaction of allenes involving a coupling between an enallene and an allenyne followed by a carbocyclization of the generated Pd-intermediate was developed. This cascade reaction afforded functionalized cross-conjugated polyenes. The enallene is initially activated by palladium and reacts with the allenyne to give the cross-conjugated polyenes.
- B?ckvall, Jan-E.,Naidu, Veluru Ramesh
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supporting information
p. 5428 - 5437
(2020/05/19)
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- Palladium-catalyzed oxidative borylative carbocyclization of enallenes
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An efficient oxidative carbocyclization/borylation of enallenes uses Pd(OAc)2 as the catalyst, B2pin2 as the boron-transfer reagent, and 1,4-benzoquinone (BQ) as the oxidant (see scheme). The reaction seems to take place through activation of the allene by a Pd II complex to give an alkenyl-PdII intermediate followed by carbopalladation of the olefin and subsequent cleavage of the intermediate palladium-carbon bond by the boron reagent. Copyright
- Persson, Andreas K. A.,Jiang, Tuo,Johnson, Magnus T.,Baeckvall, Jan-E.
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supporting information; experimental part
p. 6155 - 6159
(2011/08/07)
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- Copper-catalyzed N-Allenylation of allylic sulfonamides
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Figur Presented Allylic allenic amides have been synthesized via a copper-catalyzed cross-coupling between allylic sulfonamides and bromoallenes in moderate to good yields. Copper(I) thiophene-2-carboxylate (CuTC) was used a source of copper with DMEDA as the ligand. The allenylated products obtained are potential substrates for palladium-catalyzed carbocyclizations.
- Persson, Andreas K. A.,Johnston, Eric V.,Baeckvall, Jan-E.
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supporting information; experimental part
p. 3814 - 3817
(2009/12/06)
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- Carbon-carbon bond formation in regio- and stereoselective palladium-catalyzed cyclization of allene-substituted conjugated dienes
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Regio- and stereoselective palladium-catalyzed reactions of allene-substituted 1,3-dienes 1 in acetic acid at room temperature lead to cyclization with formation of a carbon-carbon bond between the middle carbon of the allene and the terminal carbon of the 1,3-diene. Two different types of reactions, both that constitute 1,4-carboacetoxylations of the 1,3-diene, have been developed. In one of the reactions, Pd(II) catalyzes the oxidation of 1 to bicyclic compounds 2, and in the other, Pd(0) catalyzes the transformation of 1 to bicyclic compounds 3. The products 2 are useful for further synthetic tr0nsformations and undergo Diels-Alder reactions with dienophiles to give polycyclic ring systems.
- Loefstedt, Joakim,Franzen, Johan,Baeckvall, Jan-E.
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p. 8015 - 8025
(2007/10/03)
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- Studies on Vitamin D (Calciferol) and Its Analogues. 19. Rearrangement of Vinylallenes to 1-Hydroxylated Vitamin D Model Systems Lacking the D Ring and Side Chain
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The thermally induced sigmatropic shifts of vinylallenone 7 and vinylallenol 8 were studied.The former (7) rearranges (approximately 100 deg C, 18 h) to previtamin ketone model system 13 in essentially quantitative yield; further thermolysis (approximatel
- Condran, Patrick,Okamura, William H.
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p. 4011 - 4015
(2007/10/02)
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