Radical Annulation for the Synthesis of Cyclopenta[c]chromene Derivatives

Abstract

A Cu-catalyzed oxidative radical [2 + 2 + 1] annulation reaction of phenol-linked 1,7-enynes with α-active methylene nitrile is described, affording cyclopenta[c]chromene derivatives bearing several functional groups in excellent yields. The wide substrate range, good group tolerance, and easy amplification experiments indicate the practicability of this synthesis strategy. This process provides an alternative convenient route for the synthesis of cyclopenta[c]chromene derivatives.

Propargyl Chalcones’ Radical Annulation/Sulfonation Reaction: Efficient Synthesis of Benzo[b]oxepin-5(2H)-one and Chromane Derivatives

“…The obvious disadvantage of the above-mentioned two kinds of oxygen-containing enynes is that they are difficult to obtain. Recently, we have been working on the synthesis of heterocyclic compounds via radical reactions . Herein, we would like to report an efficient process for the construction of benzo­[ b ]­oxepinone and chromane derivatives from the reactions of readily available propargyl chalcones and commercialized arylsulfonyl chloride (Scheme c,d).…”

Radical Cascade Bicyclization/Aromatization of 1,7‐Enynes with 1,3‐Dicarbonyl Compounds towards 2,3‐Dihydro‐1H‐cyclopenta[a]naphthalenes

“…Nowadays, the radical cascade reaction of 1,7enynes has been proven to be a powerful strategy to access highly functionalized polycyclic and heterocyclic compounds with the advantages of atom-and stepeconomy. [14,15] Significant advances have been made in radical cascade addition of various C-, N-, S-, or Si-centered radicals to C-, N-or O-tethered 1,7-enynes leading to the formation of structurally diverse scaffolds. [16][17][18] Nevertheless, to the best of our knowledge, using the radical cascade reaction of 1,7-enynes to construct cyclopentane-fused naphthalenes has not been reported.…”