Rhodium-Catalyzed Cross-Coupling Reaction of Arylboronates and Diazoesters and Tandem Alkylation Reaction for the Synthesis of Quaternary α,α-Heterodiaryl Carboxylic Esters
摘要:
A rhodium-catalyzed one-pot three-component coupling reaction was developed for the synthesis of quaternary alpha,alpha-heterodiaryl carboxylic esters. This reaction involves cross-coupling of the arylrhodium(I) complexes with alpha-aryldiazoacetates to form oxa-pi-allylrhodium complexes. With KOfBu and alkyl halides, tandem alkylation of the allyl complex occurs to form a quaternary stereocenter at the carbenic carbon.
Generation of bis(pentafluorophenyl)borane–dimethyl sulfide complex as a solution of hexane and its application to hydroboration of alk-1-yne with pinacolborane
A solution of bis(pentafluorophenyl)borane–dimethyl sulfide complex in hexane was generated by redistribution between tris(pentafluorophenyl)borane and borane–dimethyl sulfide complex. In the resulting solution a stoichiometric hydroboration of alk-1-yne with pinacolborane proceeded well at room temperature to afford (E)-alk-1-enylboronic acid pinacol ester in high yield. Bis(pentafluorophenyl)borane–dimethyl