Hydrogenation in Supercritical 1,1,1,2-Tetrafluoroethane(HFC 134a).

Conventional, unmodified, transition metal catalysts, substrates and reagents have sufficient solubility in sc HFC134a for organic synthesis. Reactivities (100% conversion in 2 h) and enantioselectivities (ca. 90%), comparable to those achievable in conventional organic solvents, are obtained in the asymmetric hydrogenation of a series of substrates in this alternative reaction medium using a rhodium(I)/MonoPhos catalyst.