Synthesis of Diastereoenriched 1-Indanones via Double-Base Cooperatively Promoted 1,4--Migration/Cyclization of β-Alkynyl Ketones.

A double-base copromoted 1,4--migration/cyclization cascade of β-alkynyl ketones was reported, enabling to form a range of functionalized 1-indanones with moderate to good yields and high diastereoselectivity in the presence of -BuOK as a Brønsted base and ,'-dimethylethanediamine (DMEDA) as a Lewis base. Some of these 1-indanones were successfully transformed into 2-haloethyl benzoates with one all-carbon quaternary stereocenter by 1,2-dichloroethane (DCE) or 1,2-dibromoethane (DBE) as both a reactant and a reaction media. This method also features high atomic utilization (100%), high diastereoselectivity, and mild reaction conditions.