Phospholane-based systems

In this chapter, we review the growing family of phospholane-based chiral ligands, and specifically examine their applications in the field of enantioselective hydrogenation. In general, this ligand class has found its broadest applicability in the reduction of prochiral olefins and, to a significantly lesser extent, ketones and imines this is reflected in the composition of the chapter. Several analogous phosphacycle systems have also been included, where appropriate. 

Chiral cyclic phosphines have useful properties as ligands in transition metal asymmetric catalytic systems. The most impressive example is the five-membered ring phosphorus (phospholane)-based chiral ligand DuPFIOS <2000ACR363>. 

A chiral ligand system based on C2-symmetric chiral bis(phospholanes) (5 and 6) has shown to be a powerful ligand in the asymmetric hydrogenation of various substrates that include enamides, enol acetates, C=N bond reduction, and P-keto esters. Detailed discussions of this class of ligands are included Chapter 18. 

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