Combined Rhodium/Gold Catalysis: From Propargyloxiranes to 2,5-Dihydrofurans in One Pot
作者:Özge Aksın-Artok、Norbert Krause
DOI:10.1002/adsc.201000903
日期:2011.2.11
efficient one-pot synthesis of 2,5-dihydrofuransfrompropargyloxiranes and arylboronic acids takes advantage of sequential rhodium-gold catalysis. The transformation proceeds with center-to-axis-to-center chirality transfer and tolerates a wide variety of electron-accepting or electron-withdrawing substituents at the arylboronic acid, as well as cyclic or acyclic propargyloxiranes.
Efficient silylation reactions of propargyl epoxides catalyzed by copper catalyst have been developed. Under mild reaction conditions, the tri- and tetrasubstituted functionalized allenols and alkenes could be selectively obtained in moderate to high yields via tuning the bases and solvents used in the reactions. This work provides straightforward and efficient approaches to the synthesis of multifunctionalized
Borylation of Propargylic Substrates by Bimetallic Catalysis. Synthesis of Allenyl, Propargylic, and Butadienyl Bpin Derivatives
作者:Tony S. N. Zhao、Yuzhu Yang、Timo Lessing、Kálmán J. Szabó
DOI:10.1021/ja502792s
日期:2014.5.28
Bimetallic Pd/Cu and Pd/Ag catalytic systems were used for borylation of propargylic alcohol derivatives. The substrate scope includes even terminal alkynes. The reactions proceed stererospecifically with formal S(N)2' pathways to give allenyl boronates. Opening of propargyl epoxides leads to 1,2-diborylated butadienes probably via en allenylboronate intermediate.
Stereoselective Synthesis of α-Allenols by Rhodium-Catalyzed Reaction of Alkynyl Oxiranes with Arylboronic Acids