STEREOCHEMISTRY OF SO2 INSERTION AT A CHIRAL METAL CENTER - SYNTHESIS AND CRYSTAL-STRUCTURES OF RU[C5H4(NEOMENTHYL)](CO)(PPH3)R (R = ME, SO2ME)

Reaction of (R)Ru-Ru(nmcp) (CO) (PPh3)Cl (2; nmcp = neomenthylcyclopentadienyl) with MeMgBr proceeds stereospecifically to yield (R)Ru-Ru(nmcp)(CO)(PPh3)Me (3), which reacts in liquid S02, undergoing S02 insertion to yield (R)Ru-Ru(nmcp)(CO)(PPh3)S02Me (4). The corresponding (S)Ru-Ru(nmcp)- (CO)(PPh3)Cl undergoes a similar sequence of reactions, also with retention of configuration at ruthenium. The X-ray structures of (S)Ru-Ru(nmcp)(CO)(PPh3)Me (3) and (R)Ru-Ru(nmcp)(C0)(PPh3)S02Me (4) have been determined at room temperature with use of Mo Kα radiation (λ = 0.71069 Å). Compound 3 crystallizes in the monoclinic space group P21 (C22, No. 4) with a = 8.005 (19) Å, b = 15.44 (5) Å, c = 12.974 (33) Å, ß = 102.01 (19)°, V = 1568 (7) Å3, Z = 2, and Dc = 1.291 g cm-3. On the basis of 2344 independent reflections the structure was refined to R = 0.0600. The crystals of 4 are triclinic, space group P1 (C11, No. 1), with a = 11.143 (42) Å, b = 12.108 (19) Å, c = 13.440 (27) Å, α =77.04 (14)°, ß = 78.79 (23)°, γ = 67.58 (23)°, V = 1621 (8) Å3, Z = 2, and Dc = 1.381 g cm-3. The structure was refined to R = 0.0575 on the basis of 4655 independent reflections. NMR (1H,13C, and31P) data for the individual epimers are reported, and the extent to which the CD spectrum correlates with the absolute configuration of the metal is discussed. © 1990, American Chemical Society. All rights reserved.