Syntheses of gyroscope-like molecules via three-fold ring closing metatheses of bis(phosphine) complexes trans-LyM(P((CH2)nCH=CH2)3)2, and extensions to bis(phosphite) complexes trans-Fe(CO)3(P(O(CH2)nCH=CH2)3)2

The synthesis of trigonal bipyramidal, square planar, and octahedral bis(phosphine) complexes of the formula trans-L(y)M(P((CH(2))(n)CH = CH(2))(3))(2), and their conversion to gyroscope-like molecules trans-L(y)M(P((CH(2))(2n+2))(3)P) via three-fold intramolecular alkene metathesis/hydrogenation sequences, is reviewed. New data involving bis(phosphite) complexes are then described. Reactions of P(NMe(2))(3) and HO(CH(2))(n)CH = CH(2) (n = a, 3; b, 4; c, 5; d, 6; e, 8; f, 9) a. ord the ligands P(O(CH(2))(n)CH = CH(2))(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(CH(2))(n)CH=CH(2))(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 x 6.5 mol%). NMR analyses of the resulting crude trans-Fe(CO)(3)(P(O(CH(2))(n)CH = CH(CH(2))(n)O)(3)P) (28b, e) suggest mixtures of Z/ E isomers and perhaps oligomers. Subsequent ClRh(PPh(3))(3)-catalyzed hydrogenations a. ord the title molecules trans (29b, e) as oils of 82 -83% purity by 31 P NMR. Although various properties of 29b, e can be compared to 27b, c, they could not be induced to solidify or crystallize, hampering purification. (C) 2007 Elsevier B. V. All rights reserved.