An efficient asymmetric acyl-Mannichreaction of isoquinolines with α-(diazomethyl)phosphonate and diazoacetate has been developed using chiral spiro phosphoric acids as catalysts. This reaction allowed the construction of a series of chiral 1,2-dihydroisoquinolines bearing a tertiary stereocenter at the C1 position with up to 98% yield and 99% ee.
Catalytic Asymmetric (3 + 3) Cycloaddition of Oxyallyl Zwitterions with α-Diazomethylphosphonates
作者:Yan Liu、Xian Peng、Rui She、Xin Zhou、Yungui Peng
DOI:10.1021/acs.orglett.1c02809
日期:2021.9.17
The unique structure of oxyallyls represents a significant challenge for their catalyticasymmetric applications. Herein, an unprecedented chiral imidodiphosphoric acid-catalytic enantioselective (3 + 3) cycloaddition between oxyallyl zwitterions generated in situ from α-haloketones and α-diazomethylphosphonates was developed. Pharmaceutically interesting chiral pyridazine-4(1H)-ones were obtained
novel strategy is reported here for the synthesis of an indenopyrazole scaffold bearing a phosphonate group. The entire sequence includes nucleophilicaddition–elimination, Seyferth–Gilbert homologation, transphosphorylation, and a 1,3-dipolar cycloaddition reaction of diazoalkylphosphonates in a perfect “domino” manner.
s. The reaction proceeds under mild basic conditions, making it a practical approach for the synthesis of diarylmethylated diazomethylphosphonates with a broad substrate scope. Interestingly, the treatment of the conjugate adduct with a catalytic amount of rhodium acetate resulted in the 1,2-arylmigration of the rhodium carbenoid intermediate to generate the corresponding 1,2-diaryl alkenylphosphonates
The catalytic effectiveness of ruthenium porphyrins for ylide generation in reactions of ethyl diazoacetate and diisopropyl diazomethylphosphonate with allylic amines, sulfides and iodides is described for the first time. These reactions result mainly in products of the [2,3]-sigmatropicrearrangement of intermediate allylic ylides.