Triisopropyl borate → (2,2-Difluoro-1,3-dioxaindan-5-yl)boronic acid

Participants

Reaction Steps

A solution of the title compound of Step A (15 g, 63 mmol) in tetrahydrofuran (approximately 200 mL) was cooled to -78° C. under a nitrogen atmosphere. A solution of n-butyllithium (40 mL of a 1.6M solution in hexanes) was added dropwise while maintaining the reaction temperature below -55° C. The reaction mixture was stirred at -78° C. for 20 min before a solution of triisopropylborate (29.4 mL, 127 mmol) in tetrahydrofuran (approximately 50 mL) was added dropwise over 30 min. The reaction was allowed to come to room temperature while stirring for 5 h. The reaction mixture was then partitioned between diethyl ether and 1M hydrochloric acid solution. The organic layer was separated, dried (MgSO4), filtered, and concentrated under reduced pressure to afford the title compound of Step B as a brown oil (15 g) which was used without further purification.

Provenance & Evidence