AbstractDiynes bearing one terminal and one triarylmethyl‐substituted alkyne were converted into complex benzofluorenone derivatives via a one‐pot process involving a gold‐catalyzed step followed by a photocyclization/oxidation. In the first step an N‐oxide was used to position‐selectively generate an α‐oxo carbenoid at the terminal alkyne which after a regioselective 1,6‐carbene transfer along the tethered tritylalkyne and a subsequent aryl 1,2‐shift furnished tetraphenylethylene‐like derivatives. These intermediates were successfully transformed to fluorenones via oxidative photocyclization.magnified image
AbstractDiynes bearing one terminal and one triarylmethyl‐substituted alkyne were converted into complex benzofluorenone derivatives via a one‐pot process involving a gold‐catalyzed step followed by a photocyclization/oxidation. In the first step an N‐oxide was used to position‐selectively generate an α‐oxo carbenoid at the terminal alkyne which after a regioselective 1,6‐carbene transfer along the tethered tritylalkyne and a subsequent aryl 1,2‐shift furnished tetraphenylethylene‐like derivatives. These intermediates were successfully transformed to fluorenones via oxidative photocyclization.magnified image