CHo-0-C-R CHo-0-C-R CH-0-C-R +HO →CH-0-C-R+R一C-OH 〔水解〕 CHo-0-C-R CH2-OH CH3-o-C-R CH2-o-C-R HoO 2 CH-0-C-R CH-0-C-R (縮合) H CH2-OH HC H一0-C-R