Diels‐Alder Reaction of β‐Fluoro‐β‐nitrostyrenes. Synthesis of Mono‐fluorinated Six‐Membered Derivatives

The Diels‐Alder reaction of β‐fluoro‐β nitrostyrenes with some linear dienes was investigated. A number of monofluorinated [4+2]‐cycloadducts was prepared in up to 90 % yield. The kinetics of [4+2]‐cycloaddition to 2,3‐dimethyl‐1,3‐butadiene was studied in detail to reveal substituent effect and activation parameters of the reaction. It was demonstrated that base‐induced elimination of nitrous acid followed by oxidative aromatization can be used for the preparation of mono‐fluorinated biphenyls in up to 92 % isolated yield. TOC Text: The Diels‐Alder reaction of β‐fluoro‐β nitrostyrenes with some linear dienes is reported. The kinetic studies were carried out to reveal substituent effect and activation parameters of the reaction. A new family of monofluorinated cyclohexenes 2 was prepared. The further transformation of 2 into biphenyls 3 based on base‐induced elimination of HNO2 followed by oxidative aromatization were described.