New Synthetic Methods for Seven- and Eight-Membered Cyclic Ethers Based on the Ring-Expansion Reactions of Hydroxy or Lithioxy Methoxyallenylisochroman Derivatives
The Pd(0)-catalyzed ring-expansion reactions of hydroxy methoxyallenyl-4,4-dialkylisochroman derivatives in the presence of P(o-tolyl)3 proceeded smoothly via hydropalladation to give 3-benzoxepan-1-one derivatives in high yields. Treatment of
The Palladium-Catalyzed C-H Activation of Benzylic gem-Dialkyl Groups
Palladacyclic intermediates effectively lower the high energy barrier to cleavage of a C(sp3)-H bond. C-H activation of benzylic gem-dialkyl groups of bromo- and iodobenzenes produces olefins and cyclobutabenzenes, respectively, without homocoupling (see scheme).