Lewis‐Acid‐Mediated Domino Reactions of Bis(diacetoxymethyl)‐Substituted Arenes and Heteroarenes

Abstract

A one-pot synthesis of annulated heterocycles involving a Lewis-acid-mediated domino reaction of bis(diacetoxymethyl)-substituted arenes and heteroarenes is described. The reaction of the tetraacetates with arenes and heteroarenes leads to the formation of 1,1-bis-arylated diacetates upon eli-

Synthesis of Annulated Thiophenes Involving Benzo‐DMTHFs/Triflic acid‐Mediated Domino Reactions

“…The domino reaction of 2,3‐disubstituted thiophenes 4a–c with benzo‐DMTHF 2 and triflic acid at room temperature afforded 9–2′‐thiophenyl naphtho[ b ]thiophenes 5a–c in 69–84 % yields (Table , entry 1). To our delight, the structures of the naphtho[ b ]thiophenes 5a–c could be easily assigned based on our earlier work . A similar type of naphth‐annulation could also be performed with 2‐methylfuran 4 d to furnish naphthofuran 5 d (Table , entry 2).…”

“…Under identical conditions, naphth‐annulation of 2‐methyl thiophene 10 a afforded isomeric naphtho[ b ]thiophenes 11 a and 11 a′ . Next, the domino reaction of naphtho[2,3‐ b ]thiophene 10 b with benzo‐DMTHF 2 led to the isolation of annulated thiophenes 11 b and 11 b′ (Scheme ).…”

“…As a representative case, the anthra‐annulation of substituted thiophene 4 a/10 a with naphtho‐DMTHF 24 a led to the isolation of anthra[ b ]thiophenes 25 a/25 b and 25 a′ . Based on our rearlier reports, the structures of these isomeric anthra[ b ]thiophenes could be easily assigned. Due to the solubility issues, domino reaction of anthro‐DMTHF 24 b could be performed only with the veratrole 17 a to give quinone 26 as a yellow solid (Scheme ).…”

“…Indeed, several strategies have been explored for the syntheses of naphth‐annulated arenes and heteroarenes (Figure ) through acid‐catalyzed annulation of diacetates, and tetraacetate, ZnBr 2 /SiO 2 catalyzed annulation of electron‐rich arenes with acetyl bromide‐phthalaldehydes, Lewis acid‐induced cyclization of aldehydes, A Lewis acid‐mediated annulation of 2/3‐(bromomethyl)indoles with arenes/heteroarenes, palladium‐catalyzed annulation of an in situ generated aryne annulation by o ‐halostyrene, HI/P‐mediated reductive cyclization or successive reductions followed by oxidation and Bradsher cyclization of 2‐aroylbenzoic acid, Diels‐Alder reactions of 1,3‐disubstituted benzo[ c ]furans as well as 5,6‐bis(bromomethylene)cyclohexa‐1,3‐diene, and base mediated annulation of 3‐phenylsulfonyl‐substituted isobenzofuranone with Michael acceptors . However, many of these protocols suffer from limitations such as harsh reaction conditions and low chemical yields coupled with restricted substrate scope.…”

Annulative π‐Extension (APEX): Rapid Access to Fused Arenes, Heteroarenes, and Nanographenes

“…Mohanakrishnan and co‐workers expanded their APEX chemistry to include tetraacetate 102 derived from phthalaldehyde. Catalyzed by BF 3 ⋅Et 2 O, 102 furnished a range of naphtha‐annulation products 103 in moderate yields (Scheme ) . However, additional heteroarenes are contained in the skeletons of fused heteroarenes 103 .…”