Orthogonal Syntheses of 3.2.0 Bicycles from Enallenes Promoted by Visible Light.
Andrea SerafinoDavide BalestriLuciano MarchiòMax MalacriaEtienne DeratGiovanni MaestriPublished in: Organic letters (2020)
Enallenes can be readily converted into two families of 3.2.0 (hetero)bicycles with high diastereoselectivities through the combination of visible light with a suitable Ir(III) complex (1 mol %). Two complementary pathways, namely, a photocycloaddition versus a radical chain, can then take place. Both manifolds grant complete regiocontrol of the allene difunctionalization. This is accompanied by an original 1,3-group shift using sulfonyl allenamides that deliver a congested tetrasubstituted headbridging carbon in the corresponding product.
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