RESUMO
A new class of chiral C(2)-symmetrical bisferrocenyl diamines, N1,N2-bis[(R)-1-ferrocenylethyl]-N1,N2-dimethyl-1,2-ethanediamine (1) and N1,N2-bis{(R)-1-[(S)-2-(diphenylphosphino)]ferrocenylethyl}-N1,N2-dimethyl-1,2-ethanediamine (2), were prepared from the chiral template (R)-N,N-(dimethylamino)-1-ferrocenylethylamine ((R)-FA). Compound 1 was prepared from the reaction of (R)-FA with MeI followed by nucleophilic substitution with N,N'-dimethylethylenediamine, while 2 was formed from 1 via ortho lithiation followed by electrophilic substitution with chlorodiphenylphosphine. Compound 2 reacts with Ru(DMSO)(4)Cl(2) to give trans-Ru(2)Cl(2) (3) in which the ligand is tetradentate. This complex crystallizes in the orthorhombic system: P2(1)2(1)2(1) (No. 19); a = 11.7230(4) Å, b = 16.5951(6) Å, c = 27.853(1) Å; Z = 4; R = 0.046; R(w) = 0.104. The geometry around the central metal is an octahedron with a pair of chlorine atoms trans to each other. This complex exhibits catalytic activity toward asymmetric cyclopropanation of some olefins and alkyl diazoacetates, giving enantioselectivity up to 95%.
