This describes homogeneous catalysts that are recoverable from solution by being phase selective and through host-guest interactions. An example of a method includes separating a water soluble N-heterocyclic carbene homogeneous catalyst from a solution by: (a) forming a host-guest compound between the catalyst and an inclusion compound in the solution; and (b) isolating the host-guest compound from the solution.

A homogenous process for the hydrogenation of the carboxylic acids and/or derivatives thereof in the presence of a catalyst comprising ruthenium, rhodium, iron, osmium or palladium, and an organic phosphine is described in which the hydrogenation is carried out in the presence of at least about 1% by weight water. A process for regenerating a catalyst comprising ruthenium, rhodium, iron, osmium or palladium and an organic phosphine is also described in which the regeneration is carried out in the presence of hydrogen and water.

Methods for asymmetric cis-dihydroxylation (AD) of quinones to produce cis-diols of quinones with high yield (i.e. a yield 30%) and high enantioselectivity (i.e. an enantiometric excess 30%) are disclosed. The method uses an iron-based catalyst, such as one or more Fe(II) complexes, as the catalyst, and can be performed under mild reaction conditions (e.g. a temperature 50 C. at 1 atom in open air). The method generally includes: (i) maintaining a reaction mixture at a temperature for a period of time sufficient to form a product, where the reaction mixture contains a quinone, one or more iron-based catalyst(s), and a solvent, and where the product contains a chiral cis-diol. Optionally, the method also includes adding an oxidant into the reaction mixture prior to and/or during step (i), such as a hydrogen peroxide solution.