Syntheses of gyroscope-like molecules via three-fold ring closing metatheses of bis(phosphine) complexes trans-L(y)M(P((CH(2))(n)CH=CH(2))(3))(2), and extensions to bis(phosphite) complexes trans-Fe(CO)(3)(P(O(CH(2))(n)CH=CH(2))(3))(2)
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abstract
The synthesis of trigonal bipyramidal, square planar, and octahedral bis(phosphine) complexes of the formula trans-LyM(P((CH2)nCH{double bond, long}CH2)3)2, and their conversion to gyroscope-like molecules trans-Ly{A figure is presented} via three-fold intramolecular alkene metathesis/hydrogenation sequences, is reviewed. New data involving bis(phosphite) complexes are then described. Reactions of P(NMe2)3 and HO(CH2)nCH{double bond, long}CH2 (n = a, 3; b, 4; c, 5; d, 6; e, 8; f, 9) afford the ligands P(O(CH2)nCH{double bond, long}CH2)3 (26a-f, 79-96%). Reactions of 26a,b,e,f and Fe(BDA)(CO)3 (BDA = benzylideneacetone) give trans-Fe(CO)3(P(O(CH2)nCH{double bond, long}CH2)3)2 (27a,b,e,f) as yellow or green oils in 17-64% yields after workup. Two representative complexes (27b,e) are treated with Grubbs' catalyst (2 6.5 mol%). NMR analyses of the resulting crude trans-Fe(CO)3(P(O(CH2)nCH{double bond, long}CH(CH2)nO)3P) (28b,e) suggest mixtures of Z/E isomers and perhaps oligomers. Subsequent ClRh(PPh3)3-catalyzed hydrogenations afford the title molecules trans{A figure is presented} (29b,e) as oils of 82-83% purity by 31P NMR. Although various properties of 29b,e can be compared to 27b,c, they could not be induced to solidify or crystallize, hampering purification. 2007 Elsevier B.V. All rights reserved.
