β-Hydroxyenones via Reductive Aldol Coupling of Divinyl Ketones

Significance

The process described is of particular interest in that the reaction is chemoselective for the least hindered alkene and the resulting hydroxyenone 3 does not undergo overreduction. Moreover, the diastereoselectivity is generally good to excellent, favoring the syn-aldol adducts 3 and 4. The synthetic use of the method was demonstrated by further transformations of the β-hydroxyenones 3b into polypropionate fragments 5 and 6.