Photoinduced Merging with Copper- or Nickel-Catalyzed 1,4-Cyanoalkylarylation of 1,3-Enynes to Access Multiple Functionalizatized Allenes in Batch and Continuous Flow

A three-component reaction of 1,3-enynes and cyclobutanone oxime esters in the presence of aryl boronic acids or organozinc reagents via the photoredox/copper or photoredox/nickel catalysis has been established. This redox-neutral 1,4-cyanoalkylarylation reaction has demonstrated mild condition, high catalytic reactivity and wide functional group compatibility, allowing access to a variety of functionalized tetra-substituted allene derivatives with high chemo- and regioselectivity. Moreover, using photocatalytic continuous flow technique to promote this process would result in increased yields (70% in flow vs. 61% in batch), reduced reaction times (7 min in flow vs. 6 h in batch), and easy scale-up (upgrade to gram scale), showcasing its potential as a synthetic platform.