A new method for peroxyketal synthesis is presented based upon formati
on of carbon-carbon bonds in the presence of a protected hydroperoxide
. The 2-methoxypropyl perketal of 4(S)-hydroperoxy-2(E)-nonenal (2) un
dergoes reaction with a variety of metal hydrides and organometallic r
eagents to produce 4-peroxy 2-enols in good to excellent yields via ch
emoselective addition to the carbonyl carbon. Oxidation of the allylic
alcohol to the 4-peroxy 2-enone is followed by deprotection to furnis
h a single enantiomer of a 4-hydroxyperoxy 2(E)-enone. Photochemical i
somerization by the method of Snider induces spontaneous cyclization t
o epimeric 3-hydroxy-1,2-dioxins (hydroxy endoperoxides). Acidic metha
nolysis furnishes readily separable diastereomeric perketals as single
enantiomers.