An Unexpectedly Mild Thermal Alder−Ene-Type Cyclization of Enallenes
作者:Katja Närhi、Johan Franzén、Jan-E. Bäckvall
DOI:10.1021/jo060013g
日期:2006.3.31
A mild, thermal Alder−ene reaction of enallenes has been developed. The allenic double bond acts as the “ene” and generates a carbon−carbon bond to an unactivated olefinic “enophile” in DMF at 120 °C to give [n.3.0] bicyclic systems (n = 3−5) in good yields. Except for a minor [2 + 2] cycloaddition byproduct, the reaction proceeded with complete atom economy, as there is no requirement of a catalyst
已经开发了温和的烯属烃热的Alder-ene反应。烯丙基双键充当“烯”,并在120°C下与未活化的烯烃“亲烯体”产生碳-碳键,从而以高收率得到[ n .3.0]双环体系(n = 3-5)。除了少量的[2 + 2]环加成副产物外,该反应以完全的原子经济性进行,因为不需要催化剂或其他反应物,并且在此过程中不会形成废产物。
Palladium(II)/Brønsted Acid-Catalyzed Enantioselective Oxidative Carbocyclization-Borylation of Enallenes
An enantioselective oxidative carbocyclization–borylation of enallenes that is catalyzed by palladium(II) and a Brønsted acid was developed. Biphenol‐type chiral phosphoric acids were superior co‐catalysts for inducing the enantioselective cyclization. A number of chiral borylated carbocycles were synthesized in high enantiomeric excess.
Palladium-Catalyzed Oxidative Domino Carbocyclization–Carbonylation–Alkynylation of Enallenes
作者:Chandra M. R. Volla、Jan-E. Bäckvall
DOI:10.1021/ol501862z
日期:2014.8.15
An oxidative carbocyclization–carbonylation–alkynylation reaction cascade has been developed using catalytic amounts of palladium(II) salts. The domino reaction proceeds efficiently, giving the corresponding ynones in good to excellent yields under operationally simple conditions. A wide range of aromatic and aliphatic terminal alkynes with various functional groups are tolerated under the reaction
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
Carbon−Carbon Bond Formation in Palladium(II)-Catalyzed Allylic Oxidation: A Novel Oxidative Carbocyclization of Allene-Substituted Olefins
作者:Johan Franzén、Jan-E. Bäckvall
DOI:10.1021/ja029505a
日期:2003.5.1
efficient palladium(II)-catalyzedoxidativecarbocyclization has been developed. It was found that allene-substituted olefins 1 cyclized in the presence of 1 mol % Pd(O2CCF3)2 and p-benzoquinone (2 equiv) to give bicyclic ring systems 2 in good to excellent yields. The cyclization constitutes a new type of carbon-carbon bond forming reaction between an allene and an olefin under oxidative conditions