Arylthio-Metal Exchange of α-Arylthioalkanenitriles
摘要:
The addition of BuLi, Bu3MgLi, Et2ZnBuLi, or Me2CuLi to alpha-arylthioalkanenitriles triggers an arylthio-metal exchange. NMR spectroscopic analyses implicate organometallic attack on sulfur forming a three-coordinate sulfidate as the key intermediate. Electrophilic trapping affords tertiary and quaternary nitriles in high yield. The method addresses the challenge of improving the functional group tolerance and preventing polyalkylations.
(dimethylsilyl)acetonitriles (Me2HSiCR3R4CN) react spontaneously with aldehydes in DMSO to give β-hydroxynitriles in good to high yields. The addition to ketones is effectively promoted by using MgCl2 or CaCl2. (Dimethylsilyl)acetonitrile (Me2HSiCH2CN) shows lower reactivity than the α-alkylated analogues. However, the parent reagent adds efficiently to aldehydes and ketones under catalysis by AcOLi or MgCl2.