Aromatization of the norbornadiene ligand to an .eta.-ethylcyclopentadienyl ligand in a rhodacarborane via an intermediate which contains an agostic hydrogen atom

Stereoselectivity in the Rhodium‐Catalysed Reductions of Non‐Conjugated Dienes

“…The initial endo-hydride addition product is related to an intermediate that has been characterised. [33] Hence the first deuteration occurs from the endo-direction and the second is exo-specific, now specifically confirmed by 1 H, 13 C and 2 H NMR spectroscopy. After the first addition step, dissociation/recoordination occurs selectively to the exo-face of the monoene, to which H 2 /D 2 is preferentially delivered.…”

Large-cage (11–13-vertex) dicarbon metallacarboranes of platinum metals with mono- and polycyclic diolefin ligands

“…First anionic rhodacarboranes with the 1,5-cyclooctadiene (COD) ligand at the metal vertex [PPN][3,3-( 4 -COD)-1-R-2-R 1 -3,1,2-closo-RhC 2 B 9 H 9 ] (18a-c: a R = R 1 = CH 3 ; b, R = H, R 1 = Ph; c, R = R 1 = H; PPN is the bis(triphenylphosphine)iminium cation) were prepared nearly 20 years ago by Hawthorne and co-workers [13]. These complexes were synthesized starting from the COD-rhodium dimeric complex [( 4 -COD) 2 Rh 2 (-Cl) 2 ] (19) and the corresponding dicarbollide dianions [7-R-8-R 1 -7,8-nido-C 2 B 9 H 9 ] 2− (20a-c) generated in situ from the parent dicarba-nidoundecaborate salts [K][7-R-8-R 1 -7,8-nido-C 2 B 9 H 10 ] in the presence of the strong base i-PrONa/i-PrOH.…”

“…Among these compounds are new representatives of closo-( 4 -COD)rhodacarboranes 18(d-f: d, R = CH 2 OH, R 1 = H [14]; e, R = CH CH 2 , R 1 = H; f, R = C(CH 3 ) CH 2 , R 1 = H [15]) and the related complexes with 2-R -NBD ligands, [PPN] [3,3-{ 4 -(NBD-2-R )}-1-R-2-R 1 -3,1,2-closo-RhC 2 B 9 H 9 ] (21a-k: a, R = H, R = R 1 = CH 3 [16]; b, R = CH 2 OH, R = R 1 = H; c, R = CHO, R = R 1 = CH 3 ; d, R = CH 2 OH, R = R 1 = CH 3 ; e, R = CH 2 OH, R = H, R 1 = CH 3 ; f, R = CH 2 OH, R = H, R 1 = Ph [17]; g, R = R = H, R 1 = CH 2 OH [14]; h, R = R = CH 2 OH, R 1 = H; i, R = CH 2 OH, R = i-Pr, R 1 = H; j, R = CH 2 OH, R = CH 2 Ph, R 1 = H; k, R = C(CH 3 ) 2 OH, R = R 1 = H [18]). The research has also been extended to anionic closo-rhodacarboranes with the dicyclopentadiene (DCPD) ligand bound to the metal vertex [19][20][21][22][23].…”

“…Synthesis of anionic closo-( 4 -cyclodiene)rhodacarboranes 18-a-f [13][14][15], 21a-k [14,[16][17][18], and 22a-f [19][20][21]. Scheme 5.…”

“…Several dinuclear ruthenium-iridium [49] and ruthenium-rhodium [50] complexes of the type 13 C{ 1 H} and 31 P{ 1 H}), including single-crystal X-ray diffraction study performed for complex 62b, was used to assign the structures of 62a-c. It has been unambiguously established that it was the "old" Ru atom rather than the incoming Rh or Ir atom that moved to the position of the free vertex of the starting exo-nido-ruthenacarborane 61 during the synthesis of 62a-c.…”