Catalytic, Interrupted Formal Homo-Nazarov Cyclization with (Hetero)arenes: Access to α-(Hetero)aryl Cyclohexanones.

ABSTRACT

The first examples of a Lewis-acid catalyzed (hetero)arene interrupted, formal homo-Nazarov cyclization have been disclosed. Using SnCl4 as the catalyst, alkenyl cyclopropyl ketones undergo ring-opening cyclization to form six-membered cyclic oxyallyl cations. Subsequent intermolecular Friedel-Crafts-type arylation with various electron-rich arenes and heteroarenes provides functionalized α-(hetero)arylated cyclohexanones, a scaffold present in many natural products and bioactive compounds, in yields up to 88% and diastereomeric ratios up to 121. Regiospecific arylation occurs at the α-carbon of the oxyallyl cation due to polarization caused by the ester group.