Accelerating a Mechanically Driven anti-Woodward-Hoffmann Ring Opening with a Polymer Lever Arm Effect.
Mechanical forces have previously been used to drive reactions along pathways that violate the orbital symmetry effects captured in the Woodward-Hoffmann rules. Here, we show that a polymer "lever arm effect" can provide a mechanical advantage in accelerating the symmetry forbidden disrotatory ring opening of benzocyclobutene (BCB). Addition of an α-E-alkene to the BCB mechanophore drops the force required to induce reactions on the ∼0.1 s time scale of single-molecule force spectroscopy experiments from 1370 to 920 pN.
Department of Chemistry, Duke University , Durham, North Carolina 27708, United States.
Junpeng
J
Wang
Department of Chemistry, Duke University , Durham, North Carolina 27708, United States.
Tatiana B
TB
Kouznetsova
Department of Chemistry, Duke University , Durham, North Carolina 27708, United States.
Zhenbin
Z
Niu
Department of Chemistry, University of California , La Jolla, California 92093, United States.
Arnold L
AL
Rheingold
Department of Chemistry, Duke University , Durham, North Carolina 27708, United States.
Stephen L
SL
Craig