2-Allyl-5,5-dimethyl-1,3,2-dioxaborinane (stabilized with Phenothiazine)

Example: Catalytic allylation of cyclohexanone
To a dried septum-capped 10 mL-flask with magnetic stirring bar under an argon atmosphere is added Zn(HMDS)₂ (1.2 mg, 0.0030 mmol, 0.10 mol%). After addition of dry pentane (3.0 mL, 1.0 M), allylboronate (508 mg, 560µL, 3.30 mmol) and cyclohexanone (294 mg, 3.00 mmol) are added. The mixture is stirred under an argon atmosphere at 20 °C for 36 h. After dilution with ethyl acetate is added a saturated aqueous NH₄Cl and the phases are separated. The aqueous phase is then extracted with ethyl acetate (15 mL x 3) and the combined organic layers are dried on Na₂SO₄, filtered and concentrated in vacuo. The residue is purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate = 15:1 to 2:1) to afford the corresponding homoallylic alcohol in 89% yield.