one-step synthetic protocol toward multifunctionalized m-terphenyls 5 and sulfonyl m-terphenyls 6 is developed from substituted chalcones 1 and allyl sulfone 2 in good yields via a [3C+3C] annulation. The NaH-mediated annulation features transition metal catalyst-free condition. Chalcones 1 with the functional groups tolerance are easily prepared via Claisen–Schmidt condensation of substituted benzaldehydes
quaterphenyls 3 or cyclopropanes 4 is developed from substituted chalcones 1 and sulfones 2 in good yields via a regioselective [3C+3C] or [1C+2C] annulation. The reaction features mild conditions, multisubstitution, and functional groups tolerance and is transition metal catalyst-free. The protocol provides a novel alternative to the conventional methodologies for the synthesis of quaterphenyls or
In this article, a photoredox protocol for the synthesis of furans via oxidative coupling of olefin generated in situ from cyclopropylketones with ketonic oxygen atom is presented. Moreover, bromination of furans in the presence of overstoichiometric oxidant has been achieved with high regioselectivity.
Enantioselective Seleno‐Michael Addition Reactions Catalyzed by a Chiral Bifunctional N‐Heterocyclic Carbene with Noncovalent Activation
作者:En Li、Jiean Chen、Yong Huang
DOI:10.1002/anie.202202040
日期:2022.6.7
A highly enantioselective Michael addition reaction of alkyl selenols to enones is reported. The development of a chiral bifunctional N-heterocycliccarbene (NHC)/thiourea catalyst was key in obtaining the chiral β-seleno ketones with remarkable selectivity.
A multicomponent Kröhnke reaction of chalcones with 1-(3,3,3-trifluoro-2-oxopropyl)pyridin-1-ium bromide and ammonium acetate is described. This strategy allows efficiently construction of a series of 2-trifluoromethyl pyridines with broad functional groups.