1.3- Dienes 1.4- diazides from

Lead(IV) azide yields 1,4-diazides from l,3-dienes. Whilst q cloadditions are beyond the scope of this review, the sequence of Scheme 93 is potentially important 1,3-dienes undergo asymmetric IMels-Alder reactions with an a-diloronitroso derivative of qnandrosteione with hi ee, and die N—O... 

The syn addition of iodine azide has been observed with a strained cyclobutene derivative29. Anomalous products were obtained from (i )-cyclooctenes and bicyclic (-E -cyclooctenes30,3I, e.g., 5-7. From 1,5-cyclononadiene and 1,5- and 1,6-cyclodecadiene, stereoselective transannu-lar cyclization occurred, involving acetonitrile (solvent) as the nucleophile to give 8--1032. From 1,3-dienes, benzofuran and A-acylindoles were obtained 1,2- or 1,4-diazides via the corresponding iodo azides (Section 7.2.2.4.). 

The reaction of iodine azide in acetonitrile with cyclic conjugated dienes and polyenes afforded cis-1,2- or cis- 1,4-diazides80 81 in 80-90% yield, via SN2 reaction of the azide ion with the intermediate trans-/)-iodo azides (Section 1.2.2.2). These diazides were not purified, due to their explosive nature, and their stereochemistry was deduced from the H-NMR spectrum of the cycloadducts obtained with dimethyl acetylenedicarboxylate80,81. Instead, the addition of iodine azide to. V-acyl and 7V-sulfonylindole82-83 and benzofuran83 gave mixtures of trans- and cis-2,3-diazides. 

With trisubstituted steroid alkenes, oxidative cleavage of the C—C bond was the predominant reaction97 10 . The reaction with steroidal conjugated dienes afforded mixtures of products in which diazides usually predominate102, whereas 6/J,7a-diazido-4-en-3-ones, 4-6 together with minor amounts of 7a-azido-4-en-3,6-diones were obtained from the corresponding 4,6-dien-3-onesl03. 

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