Fast racemisation of chiral amines and alcohols by using cationic half-sandwich ruthena- and iridacycle catalysts.

The lipase-catalysed resolution of alcohols and amines yields only 50 % of the desired enantiopure product. However, addition of a racemisation catalyst leads to 100 % yield in what is called a dynamic kinetic resolution (DKR). There is a need for new racemisation catalysts that are fast and compatible with the conditions of the enzymatic reaction.

Iridium/monodentate phosphoramidite catalyzed asymmetric hydrogenation of N-aryl imines.

Asymmetric hydrogenation of N-aryl acetophenone imines using iridium/PipPhos leads to very high enantioselectivities up to >99% depending on the presence of electron-donating substituents in the 2-, 3-, and 5-position of the aryl ring. If the substituent is 2-methoxy, the resultant secondary amines are easily oxidatively deprotected using trichloroisocyanuric acid to give the primary amines in good yield with full retention of enantioselectivity.