Jh. Rigby et al., HETEROCUMULENES AS 2-PI PARTNERS IN METAL-PROMOTED [6-PI-PI] CYCLOADDITION REACTIONS(2), Tetrahedron letters, 34(34), 1993, pp. 5397-5400
Alkyl and aryl substituted isocyanates and ketenes have been shown to
be useful 2pi partners in photoinitiated chromium(0)-promoted [6pi+2pi
] cycloaddition reactions.