The regioselectivity of arene-catalyzed reductive lithiation of acetals of chlorobenzaldehydes strongly depends on the form of lithium metal employed as a reducing agent. According to previous findings, naphthalene catalyzed reductions run in the presence of lithium powder (high Na content) led to competitive metalations of both aromatic carbon–chlorine and benzylic carbon–oxygen bonds. At variance
Lithiated benzyllithiums from chlorobenzyl chlorides by a DTBB-catalysed lithiation
作者:Cecilia Gómez、Fernando F. Huerta、Miguel Yus
DOI:10.1016/s0040-4039(96)02393-3
日期:1997.1
The reaction of 2-, 3- or 4-chlorobenzyl chlorides (1a-c) with an excess of lithium and a catalytic amount of DTBB (7 mol%) in the presence of different electrophiles [PriCHO, ButCHO, Et2CO, (CH2)5CO, PhCOMe, Me3SiCl] in THF at −50°C leads after hydrolysis with water, to the expected dioles or disilylated compounds 2aa-2cf.
DTBB-catalysed lithiation of chlorinated benzylic chlorides, alcohols, thiols or amines
作者:Cecilia Gómez、Fernando F Huerta、Miguel Yus
DOI:10.1016/s0040-4020(97)10402-1
日期:1998.2
presence of different electrophiles [PriCHO, ButCHO, Et2CO, (CH2)5CO, PhCOMe, Me3SiCl] in THF at −50°C followed by hydrolysis with water leads to the corresponding compounds 2. When the same DTBB-catalysedlithiation is applied to several chlorinated benzylic alcohols or mercaptans (4 or 5) it is necessary to deprotonate the starting material with BunLi; treatment of the resulting anions or amine 6 as