Communication
RSC Advances
Acknowledgements
We thank the Director, IICT for the generous support and CSIR,
New Delhi for funding through the programme TREAT XII FYP
(BSC-0116). V. M. thanks Council of Scientic and Industrial
Research for CSIR-SRF fellowship.
Notes and references
Scheme 5 Synthetic scope of boronic ester and borate salt.
1
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complex G [through the chelation of neocuproine to E followed
by oxidation or the chelation of neocuproine to A directly] by the
addition of neocuproine into the reaction mixture. G undergoes
transmetalation with the arylboronic acid to afford the cationic
aryl(neocuproine)Pd(II) species H. This is followed by the
II
migratory insertion of enone II to form Pd –alkyl complex I.
Consequent b-hydride elimination liberates the b-aryl a,b-
II
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tive elimination to give Pd(0) species F, which is oxidized by O
2
and HX, regenerating the (neocuproine)Pd(II) catalyst.
Conclusions
In conclusion, a sustainable methodology was developed for
synthetically- and pharmaceutically-important b-aryl a,b-
enones by employing oxygen as the non-toxic oxidant for two
steps of the Pd(II)-modulated oxidation of allyl alcohol and
oxidative arylation. The method eliminated the requirement of
copper salt and base by using organoboronic acids as the
surrogates of aryl halides. The reaction was highly chemo-
selective, thereby allowing access to halogen-installed b-aryl
enones that were not accessible previously.
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RSC Adv., 2014, 4, 45490–45494 | 45493