Some recent advances in the use of titanium reagents for organic synthesis

Abstract

Abstract

Synthesis and Structure Determination of Novel Chiral Imine-Alkoxytitanium Complexes

“…Although discovered less than two decades ago, [1] these advantages led to a plethora of novel titanium compounds which are used either in a stoichiometric way or catalytically and brought about enormous success in chemo-, diastereo-, and enantioselective transformations. [2] The latter rely mainly on various chiral ligands which enable complexation of the titanium. Especially titanates derived from carbohydrates, [3] tartaric acid, [4] and axially chiral biaryls [5] as well as di-and oligopeptides [6] found wide application in the enantioselective addition of nucleophiles to carbonyl compounds.…”

Synthesis and application of azolium ionic liquid tagged TADDOL catalysts

“…Yield 92%. 1 Grignard reagent was prepared from magnesium turnings (2.0 g, 83 mmol) in dry THF (80 mL) with a slow addition of bromobenzene (12.56 g, 80 mmol) in a three neck round-bottom flask fitted with a efficient condenser which has been oven dried and flushed with argon. The reaction mixture was set to reflux by itself with a controlled addition of the bromobenzene.…”

“…Yield 97%. 1 To it was added methyl vinyl ketone (1.68 g, 24.0 mmol) and was allowed to warm to room temperature and heated up to 85 °C. When TLC indicated the complete consumption of the starting materials (about three hours) the reaction was made to cool to room temperature.…”

“…1 Since then, TADDOLs have been successfully utilized as chiral scaffolds in organic synthesis. 2 Various methodologies have been implemented for the immobilization of TADDOL catalysts with the aim of improving their recyclability and reuse as well as their efficiency and stability mainly as ligands for metal catalysis.…”

“…Yield 78%. 1 (14). A reaction flask fitted with an efficient condenser was dried with hot air-gun and flushed with argon 3 times.…”