The stereochemical inversion of unbiased allylic alcohols using triphe
nylphosphine, diethyl azodicarboxylate, and benzoic acid, commonly kno
wn as the Mitsunobu reaction, was studied in three different solvents
with specific attention toward the product composition The results gen
erated for the Mitsunobu reaction of (R)-3-deuterio-2-cyclohexen-1-ol
aad the cis and trans isomers of 1-deuterio-5-methyl-2-cyclohexen-1-ol
, 1-deuterio-5-tert-butyl-2-cyclohexen-1-ol, and optically active cia
and trans 5-isopropyl-2-methyl-2-cyclohexen-1-ol all gave similar prod
uct distributions with respect to inversion rind retention at the carb
inol center as well-as sym and anti S(N)2' type addition when THF or b
enzene was used as the solvent (CH2Cl2 gave less selective product dis
tributions), Interestingly, it was found that the quasi-equatorial and
quasi-axial nature of the starting allylic alcohol does not appear to
affect the product distribution for this reaction, nor does methyl su
bstitution at the central carbon of the allylic alcohol. Sn all cases,
significant amounts (8-28%) of non-S(N)2 type products were detected
for these sterically unbiased allylic alcohols only 72-77% of the prod
uce was from S(N)2 type reaction when sterically undemanding (R)-3-deu
terio-2-cyclohexen-1-ol was subjected to Mitsunobu conditions.