(dt, J = 5.6 Hz, J = 3.2 Hz, 1H), 3.98 (dd, J = 11.5 Hz, J = 3.6 Hz, 1H), 3.75 (dd, J = 11.6 Hz, J = 2.8 Hz, 1H), 3.71–3.63 (m, 2H), 2.95–2.69 (m, 4H), 1.61 (s, 3H), 1.37 (s, 3H), 0.92 (s, 9H), 0.88 (s, 9H), 0.13–0.04 (m, 12H). 13C NMR (125 MH