Cyclohexylcarbonitriles: Diastereoselective Arylations with TMPZnCl·LiCl
摘要:
Deprotonating substituted cyclohexanecarbonitriles with TMPZnCl center dot LiCl affords zincated nitriles that diastereoselectively couple with aryl bromides in the presence of catalytic Pd(OAc)(2), and S-Phos. Steric and electronic effects influence the diastereoselectivity; 4-t-butyl-, 4-TBSO-, and 2-Me-cyclohexanecarbonitriles exert virtually complete diastereocontrol whereas modest diastereoselectivity is observed with 4-i-Pr-, 4-Me-, and 3-Me-cyclohexanecarbonitriles. The unusual diastereoselectivity trends should prove useful for synthesizing substituted cyclohexanecarbonitrile-containing pharmaceuticals.