A rhodium catalyst is reported that catalyzes the cycloisomerization of dieneynes and trienes. This cycloisomerization reaction, formally the equivalent of an unactivated Diels-Alder reaction, proceeds at room temperature with [Rh(DIPHOS)(CH2Cl2)(2)] SbF6 as the catalyst. (C) 1998 Elsevier Science Ltd. All rights reserved.
An efficient Rh-catalyst system for the intramolecular [4+2] and [5+2] cycloaddition reactions
作者:Bin Wang、Ping Cao、Xumu Zhang
DOI:10.1016/s0040-4039(00)01432-5
日期:2000.10
A new Rh-catalyst system has been developed for the [4+2] and [5+2] cycloadditionreactions. This new system shows high reactivity at room temperature and the Rh-center bears tunable phosphine ligands. Up to 1000 turnovers have been obtained for the [4+2] cycloadditionreaction at room temperature.
Nickel-catalyzed intramolecular [4 + 2] dienyne cycloadditions: an efficient new method for the synthesis of polycycles containing cyclohexa-1,4-dienes
A rhodium catalyst is reported that catalyzes the cycloisomerization of dieneynes and trienes. This cycloisomerization reaction, formally the equivalent of an unactivated Diels-Alder reaction, proceeds at room temperature with [Rh(DIPHOS)(CH2Cl2)(2)] SbF6 as the catalyst. (C) 1998 Elsevier Science Ltd. All rights reserved.
Phosphabenzenes as electron withdrawing phosphine ligands in catalysis
作者:Erin F. DiMauro、Marisa C. Kozlowski
DOI:10.1039/b101454o
日期:2002.1.23
The utility of phosphabenzenes as ligands in late transition metal catalysis is examined. Molecular orbital calculations indicate that phosphabenzenes possess a low lying LUMO permitting π-back bonding interactions. The resultant electron withdrawing nature of the phosphabenzenes is beneficial for reactions in which reductive elimination steps are rate-limiting. For example, phosphabenzenes were found to function well in nickel catalyzed [4 + 2] cycloadditions.