PMID- 36416298
OWN - NLM
STAT- MEDLINE
DCOM- 20221214
LR  - 20221222
IS  - 1477-9234 (Electronic)
IS  - 1477-9226 (Linking)
VI  - 51
IP  - 48
DP  - 2022 Dec 13
TI  - Pyridine coordination enabled stepwise PT/ET N-H transfer and metal-independent 
      C-C cleavage mechanism for Cu-mediated dehydroacylation of unstrained ketones.
PG  - 18409-18415
LID - 10.1039/d2dt03434d [doi]
AB  - A density functional theory study of copper-mediated dehydroacylation of 
      4-phenyl-2-butanone to the corresponding olefin reveals a flexible N-H transfer 
      process and a metal-independent C-C cleavage mechanism. When 
      N'-methylpicolinohydrazonamide (MPHA) acts as the activating reagent, N-H 
      cleavage can easily take place via stepwise proton transfer/electron transfer 
      (PT/ET) and the rate-determining step is C-C homolysis with a total free energy 
      barrier of 22.6 kcal mol(-1), which is consistent with experimental observation 
      of no kinetic isotope effects (KIE) at beta-H. Besides, copper is found to have 
      little influence on C-C cleavage, but is responsible for triggering single 
      electron oxidation of the pre-aromatic intermediate (PAI). When replacing MPHA 
      with picolinohydrazonamide (PHA), the second N-H transfer is 2.7 kcal mol(-1) 
      more favorable than C-C cleavage and dominates the pathway to aromatization, 
      which explains there being no C-C cleavage product well. When 
      N'-methylbenzohydrazonamide (MBHA) is adopted, the lack of pyridine coordination 
      significantly reduces the stability of Cu(II) and N-H transfer proceeds via a 
      much more difficult proton coupled electron transfer (PCET) pathway, thus making 
      N-H cleavage a rate-determining step with a total free energy barrier of up to 
      28.1 kcal mol(-1).
FAU - Hu, Zhiyun
AU  - Hu Z
AUID- ORCID: 0000-0002-2737-7452
AD  - School of Materials Science and Engineering, Taizhou University, Taizhou 318000, 
      P. R. China. huzy@tzc.edu.cn.
FAU - Li, Rongrong
AU  - Li R
AD  - State Key Laboratory for Structural Chemistry of Unstable and Stable Species, 
      Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, P. R. China.
AD  - University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
FAU - Yang, Xinzheng
AU  - Yang X
AUID- ORCID: 0000-0002-2036-1220
AD  - Department of Chemistry, University of Washington, Seattle, WA 98195, USA. 
      xyang@iccas.ac.cn.
LA  - eng
PT  - Journal Article
DEP - 20221213
PL  - England
TA  - Dalton Trans
JT  - Dalton transactions (Cambridge, England : 2003)
JID - 101176026
RN  - 0 (Protons)
RN  - NH9L3PP67S (pyridine)
RN  - 0 (Ketones)
RN  - 789U1901C5 (Copper)
SB  - IM
MH  - *Protons
MH  - *Ketones
MH  - Copper
MH  - Electron Transport
EDAT- 2022/11/24 06:00
MHDA- 2022/12/15 06:00
CRDT- 2022/11/23 06:42
PHST- 2022/11/24 06:00 [pubmed]
PHST- 2022/12/15 06:00 [medline]
PHST- 2022/11/23 06:42 [entrez]
AID - 10.1039/d2dt03434d [doi]
PST - epublish
SO  - Dalton Trans. 2022 Dec 13;51(48):18409-18415. doi: 10.1039/d2dt03434d.