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

Abstract

An Ag‐catalyzed radical cascade bicyclization/aromatization of C‐linked 1,7‐enynes with 1,3‐dicarbonyls has been achieved, providing a step‐ and atom‐economy approach for the construction of 2,3‐dihydro‐1H‐cyclopenta[a]naphthalenes, an important structural scaffold existed in biologically active compounds. From this transformation, structurally diverse 2,3‐dihydro‐1H‐cyclopenta[a]naphthalenes were obtained in moderate to good yields with high regioselectivity. Moreover, the further product derivatizations were also exemplified.

ortho-Alkynyl Benzyl Alcohols as C6 Synthons in Regioselective Construction of Polysubstituted Naphthalenes

“…We proposed that the failure for the formation of 5 H -dibenzo­[ a,d ]­cycloheptene-type product could be attributed to the steric hindrance from the two methyl groups, thus inhibiting the Friedel–Crafts-type alkylation reaction. Inspired by these preliminary results and following our previous research on the synthesis of functionalized polycyclic and heterocyclic compounds, , herein we would like to report a novel Tf 2 O-catalyzed regioselective construction of polysubstituted naphthalenes from ortho -alkynyl benzyl alcohols (Scheme b). This strategy not only offers a straightforward approach for the assembly of polysubstituted naphthalenes under metal-free conditions with high efficiency and excellent regioselectivity but also provides a new synthetic application for ortho -alkynyl benzyl alcohols, i.e., as C6 synthons to construct PAHs.…”

Nitrative bicyclization of 1,7-diynes for accessing skeletally diverse tricyclic pyrroles

“…12 Over the years, a great number of state-of-the-art and seminal achievements demonstrated the enormous potential of radical bicyclization in organic synthesis. 13 For example, the Li group 14 pioneered the nitro radical-triggered nitration-bicyclization sequence for the construction of pyrrolo[4,3,2- de ]quinolinones starting from 1,7-enynes, tert -butyl nitrite (TBN) and H 2 O (Scheme 1a). Very recently, we elaborated a photocatalytic Kharasch-type addition-based bicyclization cascade of available heteroatom-linked 1,7-diynes with trichlorobromomethane and H 2 O, delivering a series of skeletally diverse tricyclic 2-pyranones.…”