Substitutions azidotrimethylsilane

Arenediazonium tetrafluoroborates, 19 Azidotrimethylsilane, 24 N-Chlorosuccinimide, 79 Diphenyldiazomethane, 242 a-Substituted a-amino acids a-Methylbenzylamine, 185 Methyl N-benzyloxy carbonyl-a-chloro-glycinate, 186 Pivaldehyde, 249 Miscellaneous compounds Diisobutylaluminum hydride-Boron trifluoride etherate, 116 Tin(IV) chloride, 300 Amino alcohols... 

The reaction of an exocyclic methylene group with 7V-phenylselcnophthalimide (A -PSP) and azidotrimethylsilane affords cyclic / -phenylseleno-substituted azides (Table 10)97. 

Allylic azides, e.g., 1, were produced by treatment of the triisopropylsilyl enol ethers of cyclic ketones with azidotrimethylsilane and iodosobenzene78, but by lowering the temperature and in the presence of the stable radical 2,2,6,6-tetramethylpiperidine-/V-oxyl (TEMPO), 1-triso-propylsilyloxy-l,2-diazides, e.g., 2, became the predominant product79. The radical mechanism of the reaction was demonstrated. A number of 1,2-diazides (Table 4) were produced in the determined optimum conditions (Method B 16h). The simple diastereoselectivity (trans addition) was complete only with the enol ethers of unsubstituted cycloalkanones or 4-tert-butylcy-clohexanone. This 1,2-bis-azidonation procedure has not been exploited to prepare a-azide ketones, which should be available by simple hydrolysis of the adducts. Instead, the cis-l-triiso-propylsilyloxy-1,2-diazides were applied to the preparation of cw-2-azido tertiary cyclohexanols by selective substitution of the C-l azide group by nucleophiles in the presence of Lewis acids. 

Starting materials, like 141, which are accessible from alkenes by azido-selenenylation, afforded only in a few cases vinyl azides exclusively as shown by the example 141 142 (Scheme 5.19). In most cases, after oxidation of the vicinal phenylseleno azides and elimination reaction on the intermediate selenoxide, mixtures of allyl and vinyl azides were obtained. Ring opening of trialkylsilyl-substituted epoxides was utilized several times for stereoselective synthesis of vinyl azides. Thus, treatment of the frani -contigured oxiranes 143 with azidotrimethylsilane and boron trifluoride etherate yielded cis-conflgured products 145. This result was explained by the intermediate 144 which should undergo anti-elimination. On the other hand, when subjected to sodium azide in dimethylformamide, epoxides 146 were transformed into vinyl azides 148 via... 

Monomer Synthesis. Phosphoranimines bearing various combinations of 2-methoxyethoxy, 2-(2-methoxyethoxy)ethoxy and 2,2,2-trifluoroethoxy groups have been synthesized by the Staudinger reaction (9) between azidotrimethylsilane and the appropriately substituted phosphites. (11-14) Phosphites can be prepared via the reaction of the corresponding sodium alkoxide with tris-(2,2,2-trifluoroethyl)phosphite or from PCI3 and the appropriate alcohols in the presence of (CH3CH2)3N. 

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