“…The 1 H-NMR spectrum of 12 revealed that the reduction of the C-6 ketone occurred from the less hindered β-face (δ H-6β 3.65 dd, J 6β,7β ) 3.9 Hz, J 6β,19A ) 1.3 Hz). 6,11,15,16,19 When compound 12 was treated with HCl under identical experimental conditions as those for 2 and 6, only compounds 13 (65%) and 14 (14%) were isolated; thus, indicating that route A of Scheme 1 is probably the mechanism for the transformation of 19-acetoxy-18-chloro-4R-hydroxy-6-oxo-neoclerodanes to their corresponding 18-chloro-4,6-dioxo-4,5-seco-neoclerod-5( 19)ene derivatives.…”