3-Dimethylamino-2-methylpropyl chloride

Preparation of the key intermediate to this series begins by reduction of the methylene phthalide, 12a, with hydriodic acid and red phosphorus. Cyclization of the acid (26) thus obtained affords the tricyclic ketone, 27. Reaction with the Grignard reagent from 3-dimethylamino-2-methylpropyl chloride affords the... 

A 300-mL flask containing 26 mg (0.20 mmol) of anhyd nickel chloride and 63 mg (0.21 mmol) of (S)-(2-dimethylamino-3-methylbutyl)diphcnylphosphine is filled with argon after evacuation. To it are added, at — 78 C, 2.8 mL (40 mmol) of bromoethene and 131 mL (80 mmol) of l-[4-(2-methylpropyl)phenyl]ethyl-magnesium chloride (0.61 M) in diethyl ether. The mixture is stirred at 0 C for 2 d and hydrolyzed with 10% HCl. The organic layer and diethyl ether extracts from the aqueous layer are combined, washed with sat. aq NaHCO, and dried over anhyd Na2S04. After evaporation of solvent, distillation is through a short Vigreux column (70-71 rC /2 Torr) yield 6.1 g (81 %) fx](,° + 5.66 (neat). 

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