Acetic Acid → (1R)-(+)-cis-Permethric acid

Participants

Reaction Steps

To a suspension of finely divided zinc dust (0.81 g, 1.23 mmole) in acetic acid (0.99 g, 1.64 mmole) and 4 ml of ether was added, under nitrogen, a solution of (1R,4R,5S)-6,6-dimethyl-2-oxo-4-trichloromethyl-3-oxabicyclo[3.1.0]hexane (0.50 g, 1.84 mmole) from Example IA.8.(a) in 4 ml of ether. The reaction was monitored by glpc. When the glpc results indicated almost complete conversion, the reaction mixture was diluted with additional ether and water, filtered through Celite filter aid, and the organic layer was separated, dried, and evaporated to a yellow oil which was chromatographed on two 20×20 cm preparative tlc plates with CH2Cl2 as eluent. The slow running acid band was removed, extracted with CH2Cl2, and the extract was filtered and evaporated to afford (1R,3R)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (68 mg, 18% isolated yield). The optical rotation of the acid prepared in a second identical run was measured; [α]D31 =+6.2 (hexane).

Provenance & Evidence