A New Five-Membered Ring Forming Process Based on Palladium(0)-Catalyzed Arylative Cyclization of Allenyl Enones
摘要:
A palladium(0)/monophosphine catalyst promotes a novel arylative cyclization reaction of C1-, C2-, and C3-tethered allenyl enones with arylboronic acids to produce five-membered ring containing products. The regioselectivity of the process, associated with aryl group introduction into the allene moiety, depends on the length of the tether. This finding suggests that the cyclization reaction does not proceed through a carbopalladation pathway but rather via a route involving palladacycle-forming or "anti-Wacker"-type oxidative addition to the Pd-0 catalyst.
A [3+1+1+1] cycloaddition was developed among 2-arylpropene, ketone and DMSO in the presence of K2S2O8. 2-arylpropene provides three carbons, ketone offers one carbon, and DMSO as dual carbon donor contributes two carbons to the six-membered carbocycle. It gave the cyclohexene motif and spirocyclohexene skeleton. Four C−C bonds formed in this process. Both propylene and ketone could be well tolerated
在K 2 S 2 O 8存在下,2-芳基丙烯、酮和DMSO之间发生了[3+1+1+1]环加成反应。2-芳基丙烯提供三个碳,酮提供一个碳,DMSO作为双碳供体为六元碳环贡献两个碳。它给出了环己烯基序和螺环己烯骨架。在此过程中形成了四个 C-C 键。丙烯和酮都可以很好地耐受,并以有用的产率得到相应的环己烯或螺环己烯基序。基于对照实验,提出了一种可能的机制。