Readily available lithium compounds as catalysts for the hydroboration of carbodiimides and esters

Applications of catalysis in hydroboration of imines, nitriles, and carbodiimides

“…4 examples studied using 4 mol% catalyst loading, neat condition at 80 °C with 1 H NMR yield of 30-99%. 145…”

A highly efficient Ti-catalyst for the deoxygenative reduction of esters under ambient conditions: experimental and mechanistic insights from DFT studies

“…† Titanium complex 1 crystal-lizes in the monoclinic space group I2/a and the coordination polyhedron is formed by the chelation of two amido nitrogen atoms of the dianionic ligand L1, along with two chloride ions which make the titanium center adopt a distorted tetrahedral geometry around it. The observed Ti1-N1 and Ti1-N2 bond distances [1.9740(17) Å and 1.9652 (17) Å] indicate the symmetric attachment of ligand L1 to the titanium(IV) ion. These values are similar to those [2.0809(17) and 2.0286 (18), Å] and [2.046(4) and 2.064(4), Å] for analogous titanium complexes [{Ph 2 P(BH 3 )N 2 C 6 H 4 Ti(NMe 2 ) 2 ] and [{Ph 2 P(Se) NCH 2 CH 2 NPPh 2 (Se)}Ti(NMe 2 ) 2 ] respectively reported previously.…”

“…1 Zhang and co-workers demonstrated the open-shell V( iii )-complex-catalysed hydroboration of CX (X = O, N) functionalities. 15 Magnesium-catalysed hydroboration of organic carbonates, carbon dioxide, and esters was reported by Ma et al 16 and lithium-catalysed hydroboration of esters was reported by Sen et al 17 Based on the reports published so far, hydroboration has shown limited functional group tolerance and moderate substrate scope and involves the use of expensive metal catalysts. Thus, a general methodology for the hydroboration of esters with a broad substrate scope and tolerance of different functionalities, under mild conditions with inexpensive and environment-friendly catalysts, is highly desirable (Scheme 1).…”

tBuOLi-Promoted Hydroboration of Esters and Epoxides

“…The Sen group reported the efficient hydroboration of esters using two well-defined lithium complexes, 2,6-di- tert -butyl phenolate lithium and 1,1′-dilithioferrocene. 17 Recently, the Ding group reported the hydroboration of esters using a super hydride, LiHBEt 3 . 18 Apart from the aforementioned work, ester is the sole example of substrates that have been sporadically reported.…”