SEARCH Articles Figures Tables 2- ethyl esters protect carboxyl groups 2- ethyl esters, to protect carboxyl Carboxyl groups, protection Carboxyl protecting groups Carboxylation Groups, esters Ester groups Ester protecting groups Esters to protect carboxyl groups Esters, protection Ethyl 4 -carboxylates Ethyl group Ethyl protection Protection ethyl esters Protective groups esters