Fluoroalkyl isocyanates

Zhang and coworkers have developed the use of fluorous-tagged isocyanate as well as isatoic anhydride and acid chloride for the scavenging of amines for use in combinatorial as well as conventional chemistry (Figure 8.3) [30]. All reagents were readily prepared from commercially available sources, and the F-isatoic anhydride was prepared via a simple NaH-mediated alkylation of isatoic anhydride with per-fluoroalkyl halide. 

The trifluoromethyl isocyanide thus formed isomerizes to trifluoromethyl cyanide when heated, reacts with mercuric oxide to yield trifluoromethyl isocyanate, and must be stored at low temperatures otherwise it polymerizes to a yellow solid which possibly has the structure [-C( NCF3)C( NCFj)-]n- Reference has already been made to the preparation of oxazetidines from trifluoronitrosomethane and A AT-bistrifluoromethylamino-substituted allenes (see p. 100). Possibly of greater interest is the preparation in low yield of the flrst perhalogeno oxazetidines bearing no per- or poly-fluoroalkyl substituent on nitrogen (see Scheme 8). Reaction of perfluoro-l, 2-oxazetidine, r. 

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