Synthesis of new chiral ferrocenyl amine sulfide complexes and their applications as asymmetric catalysts. The structure of (R,S)-C5H5FeC5H3[CHMeNMe2][SCH3][PdCl2

Abstract

New chiral ferrocenyl sulfide ligands of the type (R,S)-C/sub 5/H/sub 5/FeC/sub 5/H/sub 3/(CHMeNMe/sub 2/)(SR), where R = Me, Et, i-Pr, n-Bu, i-Bu, t-Bu, i-Pent, Ph, CH/sub 2/Ph, p-tolyl, or 4-chlorophenyl, have been prepared by lithiation of optically active N,N-dimethyl-1-ferrocenylethylamine followed by reaction with appropriate disulfide. These compounds are air-stable and readily chelate palladium and platinum chloride to form chiral heterobimetallic complexes (R,S)-C/sub 5/H/sub 5/FeC/sub 5/H/sub 3/(CHMeNMe/sub 2/)(SR)(MCl/sub 2/) (R = Me, i-Pr, n-Pr, i-Bu, Ph, p-tolyl, 4-chlorophenyl; M = Pd,Pt). Both the ligands and the complexes were characterized by /sup 1/H and /sup 13/C NMR spectroscopy, mass spectrometry, and infrared spectroscopy. The chiral complexes are asymmetric Grignard cross-coupling catalysts. The configuration of the cross-coupling product is related to the planar chirality of the complex. The structure of (R,S)-C/sub 5/H/sub 5/FeC/sub 5/H/sub 3/(CHMeNMe/sub 2/)(SMe)(PdCl/sub 2/) (15) was determined by single-crystal X-ray diffraction measurements. Compound 15 crystallizes in the orthorhombic space group P2/sub 1/2/sub 1/2/sub 1/ with lattice parameters a = 9.226 (3) A, b = 12.219 (4) A, c = 15.448 (5) A, M/sub r/ 480.56, V = 1741.5 (8) A/sup 3/, rho(calcd) = 1.83 g/cm/sup 3/, and Z = 4. The two cyclopentadienyl rings are eclipsed and are slightly tiltedmore » with respect to each other; the dihedral angle is 3.2/sup 0/.« less