A practical and scalable synthesis of a PDE4 inhibitor KW-4490 (1) was developed. This improved synthesis features the construction of the 1-arylcyclohexene (9) by the Diels− Alder reaction followed by a newly established Brønsted acid-promoted hydrocyanation. Subsequent crystallization-induced dynamic resolution enabled the high-yield production of the desired cis-isomer (cis-8). The synthesis was achieved in seven steps in 37% overall ...
