Palladium- and nickel-catalyzed cascade enantioselective ring-opening/coupling reactions of cyclobutanones

Abstract

The chemistry of small ring compounds is an intriguing subject in organic chemistry. As the smallest stable cyclic aliphatic ketones, cyclobutanones have garnered tremendous attention owing to their intrinsic high...

DFT study on isothiourea-catalyzed C–C bond activation of cyclobutenone: the role of the catalyst and the origin of stereoselectivity

“…1 Cyclobutenones represent a class of privileged synthons, because the release of the ring strain through C–C bond cleavage of cyclobutenone can provide versatile reactive intermediates. 2…”

“…Typically, the insertion of transition metals into the C–C bond of cyclobutenone by oxidative addition gives metal-bound active intermediates (Scheme 1a). 2,3 The use of organocatalysts presents a new mode for C–C bond activation. As shown in Scheme 1b, the organocatalysis is initiated by nucleophilic addition of an organocatalyst to the carbonyl carbon of cyclobutenone to weaken the C–C bond.…”

Aryl boronic acid-controlled divergent ring-contraction and ring-opening/isomerization reaction of tert-cyclobutanols enabled by nickel catalysis

“…As with the 3-(2-bromophenyl)cyclobutanone, it could undergo the ring-contraction reaction through a palladium-catalyzed sequential ring-opening/cross-coupling reaction. 13 tert -Cyclobutanol is an alternative to the cyclobutane derivative which has been widely studied for the synthesis of γ-functionalized ketones. 14 However, the ring contraction reaction of tert -cyclobutanol has been far less developed.…”