PHOSPHA-THIAHELICENE BASED GOLD(I) COMPLEXES IN ENANTIOSELECTIVE CATALYSIS

Helically chiral structures are known to display peculiar properties and applications in many fields, including asymmetric catalysis. However, both the synthesis of helical phosphorus ligands and their uses in enantioselective organometallic catalysis have been underdeveloped so far.1 In the course of our studies on helical phosphane derivatives as potential chiral ligands in asymmetric organometallic catalysis,2 we have recently synthesized a new chiral phospha-thiahelicene based gold (I) complex 1, through a highly diastereoselective procedure. Preliminary studies on its catalytic activity have shown that 1 is an excellent and selective precatalyst for the enantioselective cycloisomerization of N-tethered enynes (up to 96% ee).3 These promising results are especially rewarding as far as enantioselectivity in gold catalysed processes remain to date a highly challenging target.