Abstract
A polymer-supported iridium catalyst has been prepared and used in the isomerisation of the double bonds in aryl allylic derivatives with excellent trans selectivity and without the need for conventional work-up procedures.
Key words
iridium - isomerisation - polymer-supported reagents
References
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1 and 2 is based on the solution-phase analogue:
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6 General Experimental Procedure: A suspension of the polymer 1 (150 mg) in THF (2.5 mL) was activated by bubbling hydrogen through the suspension until the red polymer turned chrome yellow. The reaction flask was then evacuated and filled with argon before a solution of the aryl allylic derivative (0.25 mmol) in THF (2.5 mL) was cannulated into it. The resulting suspension was agitated at room temperature for 2 h to 15 h. The polymer was removed by filtration and washed with CH2 Cl2 and THF. The filtrate was concentrated in vacuo and filtered through a plug of silica to yield the isomerised product.
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8 All reactions were stopped after 1.5 h and the reaction mixture analysed directly.
9 In a similar manner dillapiole (Table, entry 6) proceeded from quantitative to 91% to 70% (1.5 h reaction runs). The reaction die however proceed to completion when extended reaction times were used (15 h).
