Treatment of terminal olefinsbearingelectron-withdrawing groups with (R,R)-pentane-2,4-diol (2) in the presence of PdCl2–CuCl–O2 in 1,2-dimethoxyethane gives cyclic acetals such as (3) and (12b)via attack at the terminal carbon atom; the corresponding acetals are similarly formed from propane-1,3-diol (5) and ethylene glycol (8).
The diastereoselectivity of the carbonyl addition of organolithium reagents to β-ketoacetals was examined. Addition of MeLi to β-ketoacetal derived from Pd(II)-catalyzed acetalization of phenyl vinyl ketone with (R,R)-2,4-pentanediol gave (4R,6R)-4,6-dimethyl-2-[(2R)-2-hydroxy-2-phenylpropyl]-1,3-dioxane in 75%de.