All compounds obtained in this manner gave satisfactory spectroscopic data. Selected spectroscopic data for representative products are as follows. 11a (n=1, RPh): IR (neat): 3450, 1725, 1600, 1180 cm −1 . 1 HNMR (CDCl 3 ) δ: 2.85 (1H, m, CHCO), 3.18 (1H, m, CHPh), 3.30 (1H, m, HCO), 4.41 (1H, m, CHOCO), 7.24 (5H, m, aromatic-H). MS (m/z): 288 (M + ), 190, 144, 118. [α]D 26 −148.3° (c=0.12, CHCl 3 ). 11b (n=1, RPh): IR (neat): 3450, 1725, ...