Regioselective Copper-Mediated Synthesis of Thieno[2,3-c]pyrane-7-one, Indolo[2,3-c]pyrane-1-one, and Indolo[3,2-c]pyrane-1-one

Abstract

In the presence of copper(I) iodide, heteroaromatic β-iodo-α,β-unsaturated carboxylic acid systems opposed to terminal alkyne afford selectively 6-endo-dig cyclization products via a tandem coupling oxacyclization reaction.

Selective Carboxylate Directed ortho Functionalization in Copper Catalyzed Reactions of Polyiodo Aromatics: A Straightforward Preparation of 5,7‐Diiodo‐1H‐isochromen‐1‐ones

“…Based on our previous results, we started by applying our classical conditions, copper iodide (20 mol‐%) with phenylacetylene (1.2 equiv.) at room temperature . Surprisingly, no trace of expected 3‐benzylidene phthalide [( Z )‐3‐benzylidene‐4,6‐diiodoisobenzofuran‐1(3 H )‐one] 3 was detected.…”

“…Within the last decade, our group has described a new versatile route to lactones through the reaction of terminal alkynes and β‐halo‐α,β‐unsaturated carboxylic acids in the presence of a catalytic amount of copper(I) salts . This regio‐ and stereoselective reaction led to either γ‐alkylidene butenolides with a non‐aromatic β‐halo‐α,β‐unsaturated carboxylic acids as starting material, or exclusively to δ ‐alkylidene phthalides in the case of heteroaromatic substrates (Scheme ) . In the case of aromatic substrates, like 2‐iodobenzoic acid, we were pleased to demonstrate that a simple change in the temperature of the reaction could totally inverse the selectivity of the transformation to give rise to the five‐membered ring at room temperature or to the six‐membered ring with heating.…”

“…As a result of our previously established methodology, and to prepare a unified way to extend the functionalities of this interesting heterocycle, we report in this paper a very mild and convenient copper‐catalyzed route to synthesize exclusively 5,7‐diiodo‐3‐substituted isocoumarins by starting from 2,3,5‐triiodobenzoic acid (Scheme ).…”

Synthesis and Reactivity of Oxazinoindolones via Regioselective 6‐exo‐dig Iodolactonization

“…and 20 mL of water and then stirred for 30 min. The precipitate was filtered on a Büchner funnel and washed by hexane and the precipitate was left to dry for 2 h. The following products are already described and in accordance with the litterature : Ethyl 3-iodo-1Hindole-2-carboxylate (method A) 5a [16] ; Methyl 7-iodo-5H- [1,3]dioxolo [4,5-f]indole-6-carboxylate (method B) 5b [18b] ; Ethyl 5-fluoro-3-iodo-1H-indole-2-carboxylate 5d [18b] (method B).…”

“…[15] Herein, we report a new protocol for the synthesis of a variety of substituted 1,2-fused indoles under mild reaction conditions using an iodolactonization methodology. 3,4-dihydro-1H- [1,4]oxazino [4,3-a]indol-1-one 1H- [1,3]oxazino [3,4-a] indol-4(3H)-one O 3,4-dihydro-1H- [1,3]oxazino [3,4- Driven by our interest in the preparation of 1,2-fused polycyclic indoles, and in conjunction with our successful previous research on the tandem coupling/cyclization reaction of iodo-carboxylic indoles, [16] we explored the reactivity of carboxylic N-propargylic indoles in the iodolactonization reaction, followed by palladium cross-coupling functionalization of the residual iodine. This approach allows the preparation of original substituted oxazinoindolones in positions 3 and 10 (Scheme 1).…”