Re(I) tricarbonyl bipyridine and terpyridine complexes catalyse stereospecific cyclopropanation of alkenes; high selectivity of cyclopropane vs coupling and an ee of 73% and 62% for cis- and trans-cyclopropanes of styrene respectively were achieved with the [Re(L)(CO)(3)(MeCN)]OTf complex (L = chiral C(2)-symmetric terpyridine ligand).
Olefin cyclopropanation catalysed by novel ruthenium-arene complexes containing phosphines with pendent arenes
作者:François Simal、Dominique Jan、Albert Demonceau、Alfred F. Noels
DOI:10.1016/s0040-4039(99)00057-x
日期:1999.2
Ruthenium-arene complexes containing phosphines with pendent aryl groups [RuCl2(eta(6)-p-cymene)(PCy2(CH2)(3)Ar)]. Ar = C6H5 and 3,5-(CH3)(2)-C6H3 (1 and 3), and the resulting chelating complexes [RuCl2(PCy2(CH2)(3)-eta(6)-Ar)] (2 and 4) mediate the cyclopropanation of olefins with ethyl diazoacetate. Comparison of the reactivity patterns of these complexes indicates that p-cymene disengagement is likely the key step in the reactions catalysed by non-chelating complexes 1 and 3. (C) 1999 Elsevier Science Ltd. All rights reserved.
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