Synthesis of Cyclopentenones with Reverse Pauson-Khand Regiocontrol via Ni-Catalyzed C–C Activation of Cyclopropanone
Keyword(s):
A formal [3+2] cycloaddition between cyclopropanone and alkynes via Ni-catalyzed C–C bond activation has been developed, where 1-sulfonylcyclopropanols are employed as key precursors of cyclopropanone in the presence of trimethylaluminum. The transformation provides access to 2,3-disubstituted cyclopentenones with complete regiocontrol, favoring reverse Pauson-Khand products where the large substituent is located at the 3-position of the ring. In the process, the trimethylaluminum additive is thought to play multiple roles, including as a Brønsted base triggering the equilibration to cyclopropanone and liberation of methane, as well as a source of Lewis acid to activate the carbonyl group toward Ni-catalyzed C–C activation.
2016 ◽
Vol 55
(44)
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pp. 13877-13881
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2008 ◽
Vol 350
(4)
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pp. 552-556
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2017 ◽
Vol 41
(24)
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pp. 15475-15484
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2005 ◽
Vol 347
(15)
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pp. 1899-1903
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