cis-1,3-bis(formylmethyl)cyclobutane

bicyclo[3.1.1]heptan-4-one

(4-oxocyclohexyl)methyl 4-methylbenzenesulfonate

p-toluenesulfonic acid (1,4-dioxaspiro[4.5]decan-8-yl)-methyl ester

bicyclo[2.1.1]hexan-3-one