NOVELTY - Method for preparing 10-oxa-4-aza-tricyclo(5.2.1.0/2,6/)dec-8-ene-3,5-dione compounds involves: contacting a furanyl compound with a maleimide compound in an optional polar organic solvent; and heating the composition to 25-55 degrees C.    USE - For preparing 10-oxa-4-aza-tricyclo(5.2.1.0/2,6/)dec-8-ene-3,5-diones (claimed); useful as thermally labile/cleavable surfactants, in industrial processes where foaming or persistent surface-active properties are required to be diminished after their initial use, such as in green chemistry where degradability is desired; and in biomedical drug delivery where surfactants are required to be removed through biological mechanisms.    ADVANTAGE - The 10-oxa-4-aza-tricyclo(5.2.1.0/2,6/)dec-8-ene-3,5-dione compounds, include a sulfonate, such as sodium sulfonate group; provide improved thermally labile/cleavable surfactants that can be prepared by Diels-Alder (DA) reactions between functionalized furans and malemides and comprise DA adducts; as compared to the prior art surfactants containing furan-maleimide DA thermally activated weak-link, that comprise either carboxylate or phenolate polar head groups and a 12C linear alkyl chain that serves as the hydrophobic tail section, and require deprotonation of the head group through addition of an excess of potassium hydroxide to achieve solubility in water. The sulfonate-based sodium salt DA surfactants require no deprotonation step or addition of hydroxide and are soluble in water and/or polar organic solvents. The surfactants degrade into hydrophilic and hydrophobic fragments after exposure to elevated temperatures (greater than 50 degrees C) and loose all surface-active behavior. The DA surfactants comprising the simple ringed adducts can be formed at moderate temperatures (i.e. about 50 degrees C), and their dissociation occurs at temperatures above 55 degrees C. Thus, are suitable as as surface active materials for processes that require surfactant deactivation or removal using a non-invasive thermal trigger.    DETAILED DESCRIPTION - Method for preparing 10-oxa-4-aza-tricyclo(5.2.1.0/2,6/)dec-8-ene-3,5-dione of formula (I) involves: (i) contacting a furanyl compound of formula (ii) with a maleimide compound of formula (ii) in an optional polar organic solvent; and (iii) heating the composition to 25-55 degrees C.    Rn =-L-G;    L=-(hetero)aryl-, -(8-30C)alkyl-, -(6-20C)haloalkyl-, -(3-10C)cycloalkyl-, or -heterocyclyl-;    G= -S(O)2OM;    M=H, Li, Na, K, Rb, or Cs;    R=-L1-R';    L1=a bond, -(1-4C)alkyl-O-, -aryl-, or -(3-10C)cycloalkyl-;    R'=-(8-30C)alkyl, -(6-20C)haloalkyl, or -((1-4C)alkyl-O)j-Ra;    j=2-100;    Ra=H, or methyl;    m=1-4.