No abstract

A novel Lewis base-catalyzed [4 + 3] annulation process for the construction of benzo[b]oxepine scaffolds has been developed. 1,4-Diazabicyclo[2.2.2]octane (DABCO) promotes the union of o-QMs and Morita−Baylis−Hillman carbonates in reasonable to excellent yields and good stereoselectivities (dr > 20:1). This straightforward, catalytic approach offers access to a variety of synthetically useful benzo[b]oxepine derivatives bearing oxindole scaffolds containing all-carbon spiro-quaternary stereocenters.

A photocatalytic process for selective arylalkylation of allylic alcohols with α-bromo diethyl malonate has been developed. The reaction provided a straightforward approach to synthesize α-aryl-β-alkylated ketones via unique 1,2-aryl migration. The procedure is highlighted by its operational simplicity and mild reaction conditions.

A novel visible-light photoredox catalysis protocol for the effective and efficient synthesis of 3-substituted chroman-4-ones and 2,3-dihydroquinolin-4­(1H)-ones via tandem radical addition/cyclization of alkenyl aldehydes has been described. This reaction features a broad substrate scope, mild reaction conditions, and good functional group tolerance character.