Pheromone Synthesis, CLVIII. New Synthesis and Revision of the Absolute Configuration of the Hemiacetal Pheromone of the Spined Citrus Bug Biprorulus bibax

The enantiomers and the racemate of (3R,4S,1′E)‐3,4‐bis(1′‐butenyl)tetrahydro‐2‐furanol (1) were synthesized by employing Ireland's ester enolate Claisen rearrangement of 5 as the key reaction to provide the corresponding lactone 3 via 4. Optically active 3 was prepared by employing either chemical asymmetric reduction [12 → (S)‐8b] or lipase‐mediated asymmetric hydrolysis (9→10) and acetylation (meso‐2 → ent‐10) as the key transformations. The absolute configuration of the naturally occurring 1 was revised as (3R,4S) on the basis of the chemical asymmetric synthesis of (3S,4R)‐3 by starting from (S)‐8b of known stereochemistry.