Synthesis Of Butenolide Compounds Via Tandem Ring-Opening Reaction Of Vinyl Epoxides

Vinyl epoxide is constituted of strained three-membered ring and conjugate C=C moiety which could coordinate with transition metal catalyst. These structural characteristics enable vinyl epoxide as a verstile synthetic synthon in the presence of lewis acid or transition metal for heterocycles synthesis. Recently, nucleophilic catalytic reaction has become a powerful approach for the preparation of a variety of functionalized unsaturated carbocyclic and heterocyclic compounds. We pioneered the use of vinyl epoxide in nucleophilic phosphine promoted reactions.(1) This thesis focused on tertiary phosphine-mediated tandem reaction between vinyl epoxide and trifluoromethyl ketone whereas the in situ formed lactone ylide would smoothly undergo Wittig olefination with carbonyl compounds. With synthetically accessible vinyl oxirane in hand, we optimized the reaction parameters and conduct a concise investigation on the substrate tolerance with aryl CF3 ketone. An array of vinyl butyrolactones was prepared with acceptable efficiency and good geometrical selectivity.(2) Upon the conjugate addition of nucleophile, vinyl oxirane undergo tandem SN2’Ring opening reaction/lactonization sequence and afford an array of differently a-substitued butyrolactones. The obtained dehydrogen analogs of a-aminomethyl butyrolactone structure may be of potential applicant interest in medicine chemistry.