Loeber, C; Wieser, C; Matt, D; Decian, A; Fischer, J; Toupet, L; ,
The di(amide)-diphosphane hybrids 5,11,17,23-tetra-tert-butyl-25,27-bis(diethylcarbamoylmethoxy)-26,28-bis(diphenylphosphinomethoxy)calix[4]arene (cone) 7 and (R,R)-(+)-5,11, 17,23-tetra-tert-butyl-25,27-bis[(1-phenylethyl) carbamoylmethoxy]-26,28-bis(diphenylphosphinomethoxy)calix[4] arene (cone) 8 were prepared in three steps from p-tert-butylcalix[4]arene 1. Reaction of 1 with 1.1 equiv K2CO3 and 2 equiv BrCH2C(O)NR(1)R(2) (R(1) = R(2) = Et and R(1) = (R)-CHMePh, R(2) = H) proceeds via the selective alkylation of two diametrically located phenol rings and gave the di(amide)-di(hydroxy) compounds 2 and 3, respectively, both in a cone conformation. Deprotonation of 2 and 3 with 2 equiv (t)BuONa followed by alkylation with 2 equiv Ph(2)P(O)CH(2)OTs yielded the phosphane oxides 4 and 5 respectively (cone conformers). The structure of 4 was confirmed by an X-ray diffraction study. Crystal data for 4 : triclinic, space group P (1) over bar, with a = 14.316 (4) Angstrom, b = 15.272 (4) Angstrom, C = 18.100 (5) Angstrom, alpha = 86.98(2)degrees, beta = 74.93(2)degrees, gamma = 87.61(2)degrees, and Z = 2. The structure was solved by direct methods and refined to R = 0.060. Functionalization of 2 with (t)BuKO instead of (t)BuNaO led to the partial cone isomer 6 in which one phosphoryl group is positioned anti with respect to the three other pendant groups. The quantitative reduction of 4 and 5, leads to the diphosphanes 7 and 8, respectively, and was performed in refluxing PhSiH(3). The sequential reaction of [RhCl(norbornadiene)](2) with 2 equiv AgBF4 and 2 equiv 8 gave the cationic complex cis-[RhCl(norbornadiene) 8](BF4) 9. Complex 9 catalyzes the hydroformylation of styrene at 40 degrees C, under a CO/H-2-pressure of 40 bar, leading to 2-phenylpropanal and 3-phenylpropanal in a ratio 95:5. Reaction of 7 with [PtCl2(cycloocta-1,5-diene)] gave the chelate complex 10. The structure of 10 has been determined from three-dimensional X-ray data. Crystal data for 10 . CH2Cl2 : triclinic, space group P1 (1) over bar, with a = 12.481 (9) Angstrom, b = 17.558 (5) Angstrom, c = 20.43 (1) Angstrom, alpha = 95.20 (4)degrees, beta = 103.68 (8)degrees, gamma = 92.79 (4)degrees, and Z = 2. The structure was refined to R = 0.096. The phosphorus atoms are cis-bonded to the metal center and the platinum atom lies above the cavity defined by the four substituents of the calixarene. All compounds have been characterized by elemental analyses, IR and H-1, C-13{H-1} and P-31{H-1} NMR spectroscopy.