Iridium-catalysed asymmetric allylic substitutions.

Ir-catalysed allylic substitution is supplementing the traditional Pd-catalysed variant. With simple, easily available monosubstituted allylic acetates and carbonates as substrates, Ir catalysts generally favour chiral, branched products, while Pd catalysts typically give rise to linear, achiral products. With phosphorus amidites as ligands, regioselectivities >10 : 1 and enantiomeric excess in the range 95-99 %ee are currently routinely achieved. A broad range of nucleophiles can be employed: for example stabilised carbanions, amines including their sulfonyl- and diacyl-derivatives, phenolates and alkoxides. A few applications, based on combinations of the allylic substitution and ring closing metathesis, indicate considerable potential of the method for the synthesis of biologically active compounds.

Highly enantioselective iridium-catalysed allylic aminations with anionic N-nucleophiles.

Iridium-catalysed allylic substitutions with anionic N-nucleophiles were achieved with regioselectivity of up to 49:1 and enantiomeric excess of up to 98%.

Highly enantioselective syntheses of heterocycles via intramolecular Ir-catalyzed allylic amination and etherification.

[reaction: see text] Enantioselective Ir-catalyzed intramolecular allylic aminations and etherifications are described. Up to 97% ee was achieved using catalysts prepared by in situ activation of mixtures of phosphorus amidites and [Ir(COD)Cl]2. Sequential aminations of bis-allylic carbonates, involving an inter- followed by an intramolecular reaction, gave trans-N-benzyl-2,5-divinylpyrrolidine and trans-N-benzyl-2,6-divinylpiperidine with > or = 99% ee. New phosphorus amidites as well as improved conditions for intermolecular aminations are reported.