Low Valent Titanium Mediated Imino−Pinacol Coupling:  An Improved and Expeditious Route to Vicinal Diamino-Based Ligands

Samarium Metal in Organic Synthesis

“…Thus, it is interesting to observe the formation of diamines in THF with sterically congested ketimines. Mechanistically, this is in sharp contrast with the observation reported by Talukdar and Banerji [27] in their low-valent titanium induced process. These authors proposed a similar reaction pathway that involves single-electron transfer from titanium to explain the distribution of the products in their low-valent titanium induced iminopinacol-type reaction of imines.…”

“…[25] Surprisingly, analogous reactions of ketimines to the vicinal diamines proved unsuccessful. Zinc powder [26] and low-valent titanium [27] were used to achieve reductive dimerization of ketimines in an attempt to achieve a synthesis of this type of compounds. However, both attempts failed completely.…”

Indium‐catalyzed reductive coupling of aromatic carbonyl compounds and imines in the presence of aluminum and chlorosilanes

“…The structures of 1,2-diols and 1,2-diamines were determined by comparison of spectral data with those of the authentic samples reported. The structures of 7e and 7g were determined by analogy with other compounds [11,[16][17][18][19][20][21][22][23][24][25][26].…”

Titanocene-Catalyzed Coupling of Amides in the Presence of Organosilanes To Form Vicinal Diamines

“…We report herein a novel reduction–deoxygenation coupling of amides catalyzed by [Cp 2 TiX 2 ] (Cp= η 5 ‐cyclopentadienyl; X=Me or F) in the presence of a stoichiometric amount of an organosilane. To the best of our knowledge, such a reaction has not been reported previously, although the literature extensively covers the titanium‐mediated coupling of carbonyl1, 2 and imine1, 3 compounds in the presence of strong reducing agents 2. The intramolecular coupling of 1,2‐acylamido compounds to form indoles and pyrroles has also been extensively studied 4…”