An efficient Fe(OTf)3-catalyzed nucleophilicsubstitution of cyclic or acyclic tertiary alcohols with difluoroenoxysilanes is developed, which provides a facile protocol for assembling structurally diverse α,α-gem-difluoroketones featuring a quaternary carbon center in good to excellent yields under mild conditions. Moreover, the diverse product elaborations highlight the utility of this protocol,
A Highly Efficient Friedel–Crafts Reaction of Tertiary α‐Hydroxyesters or α‐Hydroxyketones to α‐Quaternary Esters or Ketones
作者:Long Chen、Jian Zhou
DOI:10.1002/asia.201200693
日期:2012.11
A catalytic Friedel–Crafts arylation of α‐hydroxyesters or α‐hydroxyketones with electron‐rich aromatic compounds to furnish α‐quaternaryesters/ketones has been developed. The cheap and easy to handle catalyst HClO4 (70 %, aq) was identified as a powerful catalyst for this arylation reaction.
The addition of arylstannanes to the carbon–heteroatom double bond in the presence of a catalytic amount of a cationic rhodium complex ([Rh(cod)(MeCN)2]BF4) was examined. The reactions of aldehydes, α-dicarbonyl compounds, and N-substituted aldimines with the arylstannanes gave corresponding alcohols, α-hydroxy carbonyl compounds, and amines, respectively. An arylrhodium complex generated by the transmetalation