287944-16-5

It plays an important role as intermediate for organic synthesis agrochemical, pharmaceutical and dyestuff field.

To a 250 mL round-bottomed flask, a solution of 3,6-dihydro-2H-pyran-4-trifluoromethanesulfonate (2.7 g, 11.6 mmol), PdCl2(dppf) (440 mg, 0.6 mmol), and potassium acetate (3 g, 36 mmol) was added to a solution of dioxane (20 mL), which was subsequently displaced three times with argon to remove air. The reaction mixture was stirred at 80 °C overnight. Upon completion of the reaction, it was cooled to room temperature and filtered through a short column containing diatomaceous earth to remove solid impurities. The filtrate was concentrated under reduced pressure and the residue was purified by column chromatography (eluent: 10% dichloromethane solution of hexane) to give the final white solid product 3,6-dihydro-2H-pyran-4-boronic acid pinacol ester (2 g, 81% yield).

[1] Patent: WO2008/153858, 2008, A1. Location in patent: Page/Page column 307
[2] Patent: US2012/316147, 2012, A1. Location in patent: Page/Page column 32
[3] Patent: WO2012/168350, 2012, A1. Location in patent: Page/Page column 76; 77
[4] ACS Medicinal Chemistry Letters, 2016, vol. 7, # 7, p. 666 - 670
[5] Patent: US2008/318935, 2008, A1. Location in patent: Page/Page column 65