This study introduces a novel protocol for the selective synthesis of cyclopentene using HT-catalysis. The key to this method is the well-defined pincer Mn-MACHOPh catalyst, which facilitates an acceptorless dehydrogenative coupling reaction. This reaction involves cyclopropyl methanol and methyl ketone, and leads to the formation of a vinyl cyclopropenone intermediate in situ. Subsequently, a radical-initiated ring expansion rearrangement takes place. Mechanistic investigations support the proposed pathway. The authors propose a new concept of cooperativity between metal catalysis and single-electron catalysis. This concept has the potential to inspire the design of cascade reactions.
Accordingly, I suggest publication after minor revisions.
1) Whether the TEMPO adducts could be captured and isolated?
2) What was the outcome of the acetophenone substrate lacking an ortho-substituent in the reaction?.
3) I am curious if 1-phenyl cyclobutyl methanol can undergo a ring expansion rearrangement.

The author has improved the manuscript as the reviewers requested. The revised manuscript is now acceptable for publication in Chem Sci.
But still minor errors should be corrected in table 2. Since the authors included an example using cyclobutyl substrate, the structures of compound 2 and product 3 should be revised accordingly.