Selective hydroboration of equilibrating allylic azides

The Iridium(I)-catalyzed hydroboration of equilibrating allylic azides is reported to provide only the anti-Markovnikov product of alk-1-ene isomers in good yields and with good functional group tolerance

Highly selective hydrosilylation of equilibrating allylic azides

Pt-catalyzed hydrosilylation of equilibrating allylic azides provides 3-azidopropansilanes with high chemoselectivity, regioselectivity, and excellent functional group tolerance.

Insight into the factors controlling the equilibrium of allylic azides

The factors controlling the allyl azides equilibrium has been studied by different theoretical approaches setting the basis to predict the regioisomers predominance in the equilibrium mixture.

Insight on the Factors Controlling the Equilibrium of Allylic Azides

<p>Several allylic azides with different double bond substitution were studied to understand the factors governing their equilibrium using density functional theory along with quantum theory of atoms in molecules, Non-covalent Interactions and Natural Bond Orbitals approaches. The results showed the hydroxyl group or heteroatoms in allylic azides interact with the molecule through an electrostatic weak interaction in each pair of regioisomers. The equilibrium shifts of substituted allylic azides, compared to non-substituted allylic azides, are not attributed to the presence of specific interactions, such as hydrogen bond. The observed equilibrium shifts stem mainly from the strengthening and weakening of negative hyperconjugative interactions, which is affected by the weak interaction involving the proximal substituent in each regioisomer. A good linear correlation was obtained between the hyperconjugative energies of pC=C→s*<i>Z</i>_b interactions and the calculated percentages of secondary azide and tertiary azides in the equilibrium mixture. Also, the effect of aromatic ring substituent was analysed using such approaches. This study not only provides insight into the factor controlling the stabilities of the substituted allylic azides, but also settle the basis to predict the regioisomer predominance in the equilibrium mixture.</p>

Insight on the Factors Controlling the Equilibrium of Allylic Azides

<p>Several allylic azides with different double bond substitution were studied to understand the factors governing their equilibrium using density functional theory along with quantum theory of atoms in molecules, Non-covalent Interactions and Natural Bond Orbitals approaches. The results showed the hydroxyl group or heteroatoms in allylic azides interact with the molecule through an electrostatic weak interaction in each pair of regioisomers. The equilibrium shifts of substituted allylic azides, compared to non-substituted allylic azides, are not attributed to the presence of specific interactions, such as hydrogen bond. The observed equilibrium shifts stem mainly from the strengthening and weakening of negative hyperconjugative interactions, which is affected by the weak interaction involving the proximal substituent in each regioisomer. A good linear correlation was obtained between the hyperconjugative energies of pC=C→s*<i>Z</i>_b interactions and the calculated percentages of secondary azide and tertiary azides in the equilibrium mixture. Also, the effect of aromatic ring substituent was analysed using such approaches. This study not only provides insight into the factor controlling the stabilities of the substituted allylic azides, but also settle the basis to predict the regioisomer predominance in the equilibrium mixture.</p>

Crystal structures of 4-{(E)-3-[(imino-λ5-azanylidene)amino]prop-1-enyl}-N,N-dimethylimidazole-1-sulfonamide and 2-[(imino-λ5-azanylidene)amino]-4-{(E)-3-[(imino-λ5-azanylidene)amino]prop-1-enyl}-N,N-dimethylimidazole-1-sulfonamide

The structures of two azide containing imidazole derivatives are reported. Allylic azides are fairly reactive making them attractive starting compounds to convert into amides. The first, C8H12N6O2S, contains one azide group with an Nα—Nβ distance of 1.229 (2) Å and an Nβ—Nγ distance of 1.128 (2) Å. The second, C8H11N9O2S, contains two azide groups with an average Nα—Nβ distance of 1.249 (2) Å and an average Nβ—Nγ distance of 1.132 (2) Å. Each compound contains a bulky protecting group (dimethylaminosulfonyl) which can be easily removed under mildly acidic conditions.

Allylic azides: synthesis, reactivity, and the Winstein rearrangement

Allylic azides are useful synthetic intermediates, the Winstein rearrangement complicates usage, and mechanistic knowledge can enable selectivity.

"It’s a (Kinetic) Trap!" – Selectively Differentiating Allylic Azide Isomers

Allylic azides are known to undergo the Winstein rearrangement and are often isolated as an equilibrating mixture of isomers. While this process has been known for almost 60 years, very few synthetic applications of this process have been reported. The absence of methods exploiting these intermediates likely stems from a paucity of approaches for gaining the required selectivity to differentiate the isomers. Our lab has made some progress in leveraging this unusual reaction into practical synthetic methodology. Presented herein is a summary of our lab’s recent accomplishments in selectively trapping allylic azides.1 Introduction2 Background: Allylic Azides3 Dynamic Cyclization of Imidates4 Summary and Outlook

Practical regio- and stereoselective azidation and amination of terminal alkenes

A metal-free synthesis of allylic azides and allylic amines was achieved under mild reaction conditions, which represents a milder alternative for azidation and amination reactions.