Diethyl Ether → (3aS,4S,6S,7aR)-3a,5,5-Trimethyl-2-(2-methylpropyl)hexahydro-2H-4,6-methano-1,3,2-benzodioxaborole

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Reaction Conditions

Reaction Steps

A 2M solution of isobutyl magnesium bromide in diethyl ether (131.5 ml, 0.263 mol) was added dropwise, in 1 hour, to a solution of 2-(1-methylethoxy)-(3aS,4S,6S,7aR)-hexahydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborole obtained in Step 1 (62.6 g, 0.263 mol), in anhydrous tetrahydrofuran (330 ml) while stirring at −78° C., under nitrogen. The mixture was then allowed to warm to room temperature, then transferred in a mixture of 2N sulfuric acid (150 ml) and diisopropyl ether (250 ml). After stirring for 10 minutes, a saturated solution of NaCl was added (100 ml) and the layers were separated. The organic phase was washed with brine (100 ml), dried over sodium sulfate and concentrated. The residue was purified by column chromatography (silica gel) eluting with 5% diethyl ether in hexane. The product was obtained as a clear oil (38.45 g, 62% yield).

Provenance & Evidence