Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Reaction of 2β-unsubstituted or functionalized-methyl 6-epipenicillin sulfoxides with tervalent phosphorus compounds gave azetidinone-epi-oxazolines , important intermediates in synthesis of 7α-methoxy-1-oxacephems. Preparation of the 2β-functionalized-methyl substrates is ...