(13) Chlorosulfonyl isocyanate is known to react with dienes in a se- quence involving initial [2 + 21 cycloaddition followed by rearrangement. (a) Moriconi, EJ; Meyer, WC J. Org. Chem. 1971,36,2841. (b) Haug, T.; Lohse, F.; Metzger, K.; Batzer, H. Helu. Chim. Acta 1968,51, 2069. (14) Benzoazetinone species have been identified aa transients in other reactions, but isolation of these unstable materials has been achieved only under select circumstances: ...