Diastereoselective [4 + 1] Cycloaddition of Alkenyl Propargyl Acetates with CO Catalyzed by [RhCl(CO)2]2
摘要:
A class of alkenyl propargyl acetates, RCH(OAc)C CC(CH3)=CH2 (5), are found to undergo [4 + 1] cycloaddition with CO (1 atm) in the presence of [RhCl(CO)(2)](2) in refluxing 1,2-dichloroethane to give cyclopentenones (6) in good yields. It has been demonstrated that, when the R group of 5 is a phenyl group bearing o-electron-withdrawing substituents up to 10:1 diastereoselectivity and 96% yield can be achieved for the [4 + 1] cycloaddition. This process provides a convenient method to construct highly functionalized cyclopentenones that are useful in organic synthesis.
type of structure units is full of challenge due to their congested chemical environment. Herein, we report a new gold(I) self-relay catalysis merging [3,3]-sigmatropic rearrangement/Nazarov cyclization with allylic alkylation starting from 1,3-enyne acetates and allylic alcohols, producing a wide range of synthetically important allyl cyclopentenones with an all-carbon quaternary stereocenter in good