Abstract
This thesis is concerned with the chemical reaction between MOB and singlet oxygen and deals with the reaction types of MOBs 22a-j and singlet oxygen: Diels-Alder reaction and rearrangement. This thesis is also looking into their possible mechanisms. We have chosen two sensitizers/ solvent systems which are Rose Bengal/ methanol and TPP/ d-chloroform and concluded that d-chloroform preferred the intermediate of biradical to form [4+2] adduct. Furthermore, methanol preferred the intermediate of perepoxide which contains higher energy to form cyclopentenone. However, without such solvent selectivity, 22i and 22j with singlet oxygen produce [4+2] adducts 26i and 26j completely both in d-chloroform and methanol . In the future, after MOB 22e reacts with singlet oxygen, the formation of natural product, Untenone A 24e, can be expected.