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
Palladium‐Catalyzed Oxidative Carbocyclization–Carbonylation of Allenynes and Enallenes
作者:Chandra M. R. Volla、Javier Mazuela、Jan‐E. Bäckvall
DOI:10.1002/chem.201402688
日期:2014.6.16
A highly efficient oxidativecarbocyclization–carbonylation reaction cascade of allenynes and enallenes has been developed using a PdII salt in low catalytic amounts under ambient temperature and pressure (1 atm of carbon monoxide). The use of DMSO as an additive was found to be important for an efficient reaction. A wide range of alcohols as trapping reagents were used to give the corresponding esters
Efficient Reoxidation of Palladium by a Hybrid Catalyst in Aerobic Palladium-Catalyzed Carbocyclization of Enallenes
作者:Eric V. Johnston、Erik A. Karlsson、Staffan A. Lindberg、Björn Åkermark、Jan-E. Bäckvall
DOI:10.1002/chem.200900980
日期:2009.7.13
Reoxidation: Smooth palladium‐catalyzed aerobic CC bond formation takes place in essentially quantitative yield with a hybrid catalyst (see scheme, E=CO2Me, R=R′=Me or R,R′=(CH2)5) through facilitated electron transfer from reduced palladium to molecular oxygen.
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 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