Stereoselective Synthesis of Highly Functionalized Indanes and Dibenzocycloheptadienes through Complex Radical Cascade Reactions

Abstract

Two highly stereoselective radical‐mediated syntheses of densely functionalized indanes and dibenzocycloheptadienes from ortho‐vinyl‐ and ortho‐vinylaryl‐substituted N‐(arylsulfonyl)‐acrylamides, respectively, are presented here. The chemoselective addition of in situ generated radicals (X.) onto the styrene moieties triggers an unprecedented reaction cascade, resulting in the formation of one new CX bond and two new CC bonds, a formal 1,4‐aryl migration, and the extrusion of SO2 to generate an amidyl radical intermediate. This intermediate, upon H abstraction, leads to the observed 5‐ and 7‐membered ring carbocyclic products, respectively, in a highly efficient manner.

Cyclic Hypervalent Iodine Reagents for Atom‐Transfer Reactions: Beyond Trifluoromethylation

“…Chemie the molecule,t hereby allowing more complex cascade processes (Scheme 9). [34] Theintroduction of an ortho-alkynyl group on the aryl sulfone allowed the formation of atetracyclic heterocycle (Scheme 9A). [34a] Thea ddition of the azide radical could also be initiated on an alkene on the aryl sulfone to generate ah ighly substituted indane product (Scheme 9B).…”

Chemo- and Regioselective Distal Heteroaryl ipso-Migration: A General Protocol for Heteroarylation of Unactivated Alkenes

“…Particularly, the scope of this reaction was mainly limited to 1,2-migration of an aryl group (Scheme A) . There are also a few cases of distal aryl migration dependent upon certain substrates . Recently, we have disclosed the first example of distal cyano migration with azidation of unactivated alkenes (Scheme B) .…”

Visible Light-Mediated Decarboxylation Rearrangement Cascade of ω-Aryl-N-(acyloxy)phthalimides

“…3 We recently reported the application of this strategy for the synthesis of (spiro)anellated furans (Scheme 1) 4 and questioned whether a similar spirocyclization would occur onto aryl rings leading to intermediates such as A (Scheme 1), a pathway reported for certain predisposed compounds (e.g., p-OH-substituted derivatives). 5 We envisioned that this way the classes of biologically important phenylethylamines, tetrahyrodoisoquinolines, or benzoazepinones (Figure 1) could be assessed from readily available starting materials, making use of renewable resources, i.e., benzoic and amino acids. 6 Our study began by using 1a as model substrate (Table 1) that was irradiated in an aqueous acetonitrile solution with a blue light emitting diode (LED, λ max = 455 nm) in the presence of catalytic amounts of photocatalyst [Ir(dtbbpy)(ppy) 2 ]PF 6 (1 mol %; ppy = 2-phenylpyridine; dtb-bpy = 4,4′-di-tert-butyl-2,2′-dipyridyl).…”