jo5014806_si_001.pdf (2.82 MB)
Catalytic Asymmetric Synthesis of Sterically Hindered Tertiary α‑Aryl Ketones
journal contribution
posted on 2014-10-03, 00:00 authored by Robert Doran, Patrick J. GuiryThe
catalytic asymmetric synthesis of a series of tertiary α-aryl
cyclopentanones and cyclohexanones has been accomplished via a Pd-catalyzed
decarboxylative protonation of the corresponding α-aryl-β-keto
allyl esters. Enantioselectivities of up to 92% ee and 74% ee were achieved for cyclopentanone and
cyclohexanone substrates, respectively. The route described gives
access to these important structural motifs in moderate to high levels
of enantioselectivity. In particular, this is only the second direct
approach for the preparation of tertiary α-aryl cyclopentanones.
The synthetic approach allows for simple modification of the aryl
group. Significantly, substrates containing sterically hindered aryl
groups gave the highest levels of enantioselectivity, and these aryl
groups were readily installed by a Pb-mediated arylation of a β-keto
allyl ester.