Exceptionally active yttrium-salen complexes for the catalyzed ring opening of epoxides by TMSCN and TMSN(3).

Halide or alkoxide free yttrium-salen complexes are excellent catalysts for the ring opening of epoxides mediated by TMSCN and TMSN3. Substrate to catalyst ratios up to 10000 have been realized in these potentially useful reactions, which can be run under solvent-free conditions. Even though the enantioselectivities for the TMSCN-mediated reaction remains modest (best 77% ee), these studies with a highly tunable ligand system may provide further impetus for work in this important area of catalysis. Even though attempts to isolate a Y-cyanide complex, which was detected by in situ IR spectroscopy, failed, a related dimeric hydroxide complex was isolated. A kinetic study using in situ IR spectroscopy did not provide conclusive data to assign an order with respect to Y in this reaction.