ethyl 2-ethenyl-3-hydroxy-5-methoxy-3-methylpentanoate

ethyl 5-hydroxy-7-methoxy-5-methylhept-2-enoate

ethyl 5-(furan-2-yl)-5-hydroxypent-2-enoate

2-(Furan-2-yl-hydroxy-methyl)-but-3-enoic acid ethyl ester

ethyl 4-(1-formylnaphthalen-2-yl)oxybut-2-enoate