Divergent synthesis of chiral cyclic azides via asymmetric cycloaddition reactions of vinyl azides.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31320649.
- Also identified by DOI 10.1038/s41467-019-11134-8 and PMC identifier 6639305.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Vinyl azides, bearing conjugated azide and alkene functional groups, have been recognized as versatile building blocks in organic synthesis. In general vinyl azides act as 3-atom (CCN) synthons through the fast release of molecular nitrogen and have been extensively utilized in the construction of structurally diverse N-heterocycles. Keeping the azide moiety intact in organic transformations to synthesis chiral azides is an important but challenging task. Herein, we report an enantioselective copper(II)/BOX-catalyzed cycloaddition of vinyl azides, generating diverse chiral cyclic azides. α-Aryl substituted vinyl azides react with unsaturated keto esters through an inverse-electron-demand hetero-Diels-Alder reaction to afford chiral azido dihydropyrans with excellent enatioselectivities. In contrast, cyclohexenyl azides undergo a diastereo- and enantio-selective Diels-Alder reaction giving important azido octahydronaphthalenes with three continuous stereogenic centers. Notable features of these reactions include a very broad scope, mild reaction conditions and 100% atom economy.