Catalytic Enantioselective Synthesis of Indanes
Stereocontrolled cyclization reactions represent formidable tools for constructing complex structural scaffolds of natural and biologically active molecules and the development of new cyclization methodologies continues to attract enormous interest in organic chemistry. Martin Smith’s group at the University of Oxford (UK) has been interested in the application of asymmetric phase-transfer catalysis to new reaction manifolds – particularly cyclizations – for some time. The use of chiral ammonium salts turned out to discriminate between the π-faces of a delocalized anion, which offered an approach to asymmetric electrocyclic reactions. Application of this effective strategy led to the generation of complex indolines with high levels of diastereo- and enantioselectivity. The aim was to extend this chemistry to the synthesis of indanes – recognizing that an alternative cyclization through a Dieckman-type process could compete – so the scene was set for a competition between an electrocyclic/5-endo-trig manifold and a 5-exo-trig alternative.
Read here the full article for free Catalytic Enantioselective Synthesis of Indanes