A solution of (2S)-methyl 2-(7-(4-allylchroman-6-yl)-2-(2′-hydroxy-[1,1′-biphenyl]-3-yl)-5-methylpyrazolo[1,5-a]pyrimidin-6-yl)-2-(tert-butoxy)acetate (0.350 g, 0.567 mmol) in dry THF (12 ml) was treated sequentially with allyl alcohol (0.116 ml, 1.700 mmol), Ph3P (0.446 g, 1.700 mmol) and DEAD (0.269 ml, 1.700 mmol), and the reaction was stirred for 2 h. The reaction was concentrated, and the residue was purified by biotage (24 g SiO2, 0% (3 CV), 0-60% (15 CV), 60% (2 CV), EtOAc in hexane). The residue after concentration was taken up in Et2O (20 mL) and washed with water (2×20 mL) to remove residual allyl alcohol, then dried (MgSO4), filtered, and concentrated, affording the desired product (0.4 g, 0.6 mmol, quant.) as a viscous clear oil. 1H NMR (500 MHz, CDCl3) δ 8.11-8.04 (m, 1H), 7.90-7.84 (m, 1H), 7.58-7.36 (m, 5H), 7.35-7.29 (m, 1H), 7.06 (t, J=7.4 Hz, 1H), 7.02-6.93 (m, 2H), 6.90 (s, 1H), 6.04-5.91 (m, 1H), 5.90-5.78 (m, 1H), 5.37-5.30 (m, 4H), 5.27-5.13 (m, 4H), 5.12-5.02 (m, 2H), 4.55 (d, J=4.9 Hz, 2H), 4.30 (br. s., 2H), 3.82 (s, 3H), 2.68-2.63 (m, 3H), 1.01-0.93 (m, 9H). LCMS (M+H)=658.6.
