Carbon−Carbon Bond Formation in Regio- and Stereoselective Palladium-Catalyzed Cyclization of Allene-Substituted Conjugated Dienes
作者:Joakim Löfstedt、Johan Franzén、Jan-E. Bäckvall
DOI:10.1021/jo0157324
日期:2001.11.1
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
Palladium-Catalyzed Oxidative Borylative Carbocyclization of Enallenes
作者:Andreas K. Å. Persson、Tuo Jiang、Magnus T. Johnson、Jan-E. Bäckvall
DOI:10.1002/anie.201008032
日期:2011.6.27
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 PdII complex to give an alkenyl–PdII intermediate followed by carbopalladation of the olefin and subsequent cleavage of the intermediate palladium–carbon
Palladium(II)-Catalyzed Oxidative Carbocyclization of Aza-Enallenes
作者:Andreas K. Å. Persson、Jan-E. Bäckvall
DOI:10.1002/anie.201000726
日期:2010.6.21
Live and let diene: A palladium(II)‐catalyzedoxidative carbocyclization reaction of aza‐enallenes provides access to potentially valuable heterocyclic dienes. In the presence of a dieneophile during the carbocyclization step, the products can react further in a one‐pot cyclization/Diels–Alder sequence to give polycyclic products. BQ=para‐benzoquinone.
Nucleophilic reactions in the series of α-haloallenes
作者:M.V. Mavrov、E.S. Voskanyan、V.F. Kucherov
DOI:10.1016/s0040-4020(01)82859-3
日期:1969.1
A new method of synthesis of functionally substituted α-bromoallenes on the basis of 1,4-dibromobuta-1,2-diene has been developed. α-Bromoallenes are shown to react with nucleophilic reagents with allene-acetylene rearrangement thus affording high yields of functionalized acetylenic derivatives of hitherto unknown types. In contrast to this, the interaction of methyl 4-bromobuta-1,2-dienoate with amines
Pd-Catalyzed Borylative Cyclization of Allenynes and Enallenes
作者:Virtudes Pardo-Rodríguez、Juan Marco-Martínez、Elena Buñuel、Diego J. Cárdenas
DOI:10.1021/ol9017694
日期:2009.10.15
Pd-catalyzed cyclization of 1,5- and 1,6-allenynes and 1,5-enallenes with bis(pinacolato)diboron affords synthetically useful allylboronates and alkylboronates under smooth conditions in a formal hydroborylative carbocyclization reaction. One C−C and one C−B bond are formed in a single operation. The reaction outcome implies that different mechanisms operate for the reactions of allenynes and enallenes