Cyclopropanation and Isomerization Reactions of β-Diketiminato Boron Complexes

The reaction of HC­[(CBut)­(NAr)]2Li with BCl3 yielded the azaallyl boron dichloride
[ArNC­(But)­C­(H)­C­(But)­N­(Ar)]­BCl2 (1), which can
be converted to the β-diketiminato boron dichloride HC­[(CBut)­(NAr)]2BCl2 (2) upon heating at 40 °C. Reaction of 1 with
the bulky lithium salts LiN­(SiMe3)2 and MesLi
(Mes = 2,4,6-Me3C6H2) resulted in
the cyclopropanation of the CBut group
via the deprotonation of the methyl group, while reactions with PhLi
and LiNEt2 gave substitution products.

HC[(CBut)(NAr)]₂Li（其中But为叔丁基、Ar为芳基）与三氯化硼（BCl₃）反应，得到氮杂烯丙基二氯化硼（azaallyl boron dichloride）[ArN=C(But)CHC(But)NAr]BCl₂（化合物1）；该化合物在40℃加热条件下可转化为β-二亚胺基二氯化硼（β-diketiminato boron dichloride）HC[(CBut)(NAr)]₂BCl₂（化合物2）。化合物1与大位阻锂盐双(三甲基硅基)氨基锂（LiN(SiMe₃)₂）以及均三甲苯基锂（MesLi，其中Mes=2,4,6-三甲基苯基）发生反应时，通过甲基去质子化过程使CBut基团发生环丙烷化反应；而化合物1与苯基锂（PhLi）、二乙基氨基锂（LiNEt₂）反应则得到取代产物。