• The 3-phenylpropionate (dihydrocinnamoyl) ester has been used as a protecting group in nucleoside synthesis: Tetrahedron Lett., 733 (1969). It can be cleaved enzymatically with ɑ-chymotrypsin at pH 7.8; acetate esters are unaffected: J. Org. Chem., 38, 977; 3575 (1973).