Ruthenium catalysts for carbenoid intramolecular C–H insertion of 2-diazoacetoacetamides and diazomalonic ester amides

Oxidative-addition of the N–H bond of saccharin (sacH) to a triosmium centre: Synthesis, structure and reactivity of Os3(CO)10(μ-H)(μ-sac)

“…The organometallic chemistry of the sac has been relatively neglected and only a few organometallic sac complexes are known [4][5][6][7][8]. In 1987, Beck and co-workers reported sac complexes of the Group VI metal carbonyls Na[M(CO)5(κ 1 -(N)-sac)] from the reactions of M(CO) 5(thf) and Na(sac) [8].…”

“…Both of these complexes undergo axial carbonyl substitution in the presence of 2-electron donor ligands to give substituted diruthenium complexes [4]. Further, A and B are suitable pre-catalysts for the cyclopropanation of nucleophilic alkenes with methyl diazoacetate [4], the later has also been found to catalyze the intramolecular carbenoid C-H insertion of α-diazo esters leading to the formation of β-and/or γ-lactams [5,6].…”

3,3’’-Bis(saccharin-6-ylmethyl)-1,1’:3’,1’’-terphenyl – Precursor of A New Tetradendate Bis-bridging Ligand

“…While the tpsac ligand in complex 19 adopts the head-to-tail arrangement (vide infra), the monoPPh 3 complex 20 is likely to have the head-to-head constitution, with the PPh 3 ligand occupying the sterically less congested axial position, in agreement with the known molecular structure of the analogous complex [Ru 2 (CO) 5 [Ru 2 (CO) 4 (PPh 3 )(µ,µ-tpsac)] with no axial CO ligand (Scheme 4). It should be noted that the 1 H and 13 C NMR spectra of the tpsac complexes reported here in all cases show more signals than expected from their composition. This is likely due to the presence of the mterphenyl-3,3 -dimethyl bridge, which can exist in different diasteroisomeric conformations that are stable on the NMR time scale.…”

“…N-Protection with NaH/benzyl bromide in DMF [27] gave 12, which was converted into (Nbenzylsaccharin-6-yl)boronic acid pinacol ester (13) by Pd-catalyzed boration. The boration of unprotected 6-bromosaccharin (11) under the same conditions has been described in a patent [28], but the product was obtained with insufficient purity.…”

“…1) [17]. Both types of complexes were active catalysts for carbenoid reactions of diazo compounds (cyclopropanation, intramolecular C-H insertion) [11,13,17], although a significant advantage over simple dirhodium tetracarboxylates could not be seen. Taber's first dirhodium complex with a tethered dicarboxylate ligand was highly efficient and effective in an intramolecular carbenoid C-H insertion [15].…”