W, at each occurrence, is independently selected from the group consisting of aryl, cycloalkyl, and heterocyclyl groups wherein W optionally consists of one or more substituents in addition to T;

T, at each occurrence is independently selected from the group consisting of —C(O)—OR¹⁶, —C(O)—NR¹⁷R¹⁸, —C(O)—N(R¹⁷)OR¹⁸, substituted and unsubstituted oxazole, substituted and unsubstituted oxazoline, and substituted and unsubstituted oxazolidine groups;

R¹ is selected from the group consisting of substituted and unsubstituted aryl, substituted and unsubstituted alkyl, substituted and unsubstituted alkenyl, substituted and unsubstituted cycloalkyl, and substituted and unsubstituted ferrocenyl groups;

R¹⁴ and R¹⁵ are independently selected from the group consisting of —H, substituted and unsubstituted alkyl, substituted and unsubstituted cycloalkyl, and substituted and unsubstituted aryl; or R¹⁴ and R¹⁵ may join together to form a substituted or unsubstituted aryl, a substituted or unsubstituted cycloalkyl, or a substituted or unsubstituted cycloalkenyl group;

R¹⁶, R¹⁷ and R¹⁸ are each independently selected from the group consisting of —H, and substituted and unsubstituted alkyl, substituted and unsubstituted aryl, substituted and unsubstituted aralkyl, substituted and unsubstituted heterocyclyl, substituted and unsubstituted heterocyclylalkyl groups; or R¹⁷ and R¹⁸ may join together to form a non-aromatic heterocyclyl group; and

the dashed line represents a single or double carbon-carbon bond.