The chemistry of pentavalent organobismuth reagents. Part 8. Phenylation and oxidation of alcohols by tetraphenylbismuth esters
作者:Derek H. R. Barton、Jean-Pierre Finet、William B. Motherwell、Clotilde Pichon
DOI:10.1039/p19870000251
日期:——
Tetraphenylbismuth trifluoroacetate under neutral or slightly acidic conditions O-phenylates primary alcohols in reasonable (65–75%) yield, but gives only moderate yields with secondary alcohols and no O-phenylation with tertiary alcohols. An SN2 type mechanism is proposed with attack of oxygen on aryl carbon. In contrast, the reaction of BiV reagents with alcohols under basic conditions gives, exclusively
下中性或微酸性条件Tetraphenylbismuth三氟ö -phenylates在合理(65-75%)产率的伯醇,但只给出中等产率与仲醇和没有ö -phenylation与叔醇。提出了一种S N 2型机理,其中氧攻击芳基碳。相反,在碱性条件下,Bi V试剂与醇的反应通常仅以苯作为离去基团进行氧化。使用核磁共振光谱已通过几种不同方式证明了具有铋-氧键的Bi V中间体的存在。因此,醇与Bi V试剂的反应与相应的与酚的反应平行。