Cwg. Fishwick et al., DITHIOLANE-ISOCYANATE IMMINIUM METHYLIDES - A RAPID STEREOSELECTIVE ENTRY INTO GAMMA-LACTAMS, Tetrahedron letters, 36(51), 1995, pp. 9409-9412
Methods have been developed for the generation and trapping of dithiol
ane-isocyanate imminium methylides which are a new type of azomethine
methylide-derived 1,3-dipole. These species add efficiently and stereo
selectively to electron deficient olefins yielding novel dithiolane-pr
otected gamma-lactans which can be efficiently deprotected to yield to
corresponding lactam systems.