Rearrangement of allyl azides

Intramolecular reactions including rearrangements such as the Overman rearrangement or rearrangement of allylic azides, and reactions of non-allylic trichloro-(fluoro)acetimidates, carbamates, etc. 

Isomerizations of allylic azides also appear to involve concerted, non-ionic rearrangements. Butenyl and pentenyl azides isomerize slowly at room temperature in a variety of solvents, viz. 

Equilibrating mixtures of allylic azide-containing allylic alcohols or allylic 2-tolylsulfonylacetic esters undergo Johnson-Claisen or Ireland-Claisen rearrangement to give unsaturated y-azido esters and acids, respectively (Scheme 8). ... 

Schkeryantz and Pearson (59) reported a total synthesis of ( )-crinane (298) using an intramolecular azide-alkene cycloaddition (Scheme 9.59). The allylic acetate 294 was first subjected to an Ireland-Claisen rearrangement followed by reduction to give alcohol 295, which was then converted into the azide 296 using Mitsunobu conditions. Intramolecular cycloaddition of the azide 296 in refluxing toluene followed by extrusion of nitrogen gave the imine 297 in quantitative yield. On reduction with sodium cyanoborohydride and subsequent reaction with... 

Besides commonly used TsN=IPh, TsNs can also be employed as a nitrene source. Bach and Korber have recently reported an Fe(iii)-catalyzed imidation of allyl sulfides 200 with iV-/ //-butyloxycarbonyl azide (BocNs), followed by [2,3]-sigmatropic rearrangement (Scheme 21). " The azide reacts with FeCl2 to generate Fe(iv) nitrene complex 201, which then reacts with allyl sulfide 200, to give an intermediate sulfimide 203, presumably through Fe(iii) intermediate 202. 

It has been found that the thermodynamic ratio of isomeric allylic azides, interchangeable by stereoselective [3,3]-sigmatropic rearrangement, can be affected by steric and electronic factors in the presence of a bulky (chiral) auxiliary. Under Mit-sunobu conditions, treatment of allylic alcohols (48 R Ph) was shown to give a... 

Basic hydrolysis of the allylic azide affords the rearranged 1,2-isomer, which was an intermediate in the synthesis of (+)-conduramine E. Following a similar strategy, but starting with dr-3,6-dibenzoyloxycyclohex-l-ene, a total synthesis of the nonopioid analgesic (—)-epibatidine was developed. ... 

Simple allylic azides undergo rearrangement at moderate temperatures. For pentenyl and butenyl azides the forward and backward reactions follow first order kinetics and the rate is insensitive to methyl substitution or the nature of the solvent . Significantly in pentane, ether and 70 % acetone, AS = —10 and — 11 eu for a,a-dimethyl and y,y-dimethyl allylazides, respectively, and cyclic intermediates were proposed, viz. 

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