Directed Lithiation of N %26apos;-[2-(4-Methoxyphenyl)ethyl]-N,N-dimethylurea and tert-Butyl [2-(4-Methoxyphenyl)ethyl]carbamate

作者：Smith Keith^*; El Hiti Gamal A; Alshammari Mohammed B

来源：Synthesis, 2014, 46(3): 394-402.

DOI：10.1055/s-0033-1338570

• directed lithiation
• side-chain lithiation
• N %26apos
• -[2-(4-methoxyphenyl)ethyl]-N,N-dimethylurea
• tert-butyl [2-(4-methoxyphenyl)ethyl]carbamate
• electrophile

N%26apos;-[2-(4-Methoxyphenyl)ethyl]-N,N-dimethylurea and tert-butyl [2-(4-methoxyphenyl)ethyl]carbamate are doubly lithiated on the nitrogen and ortho to the directing metalating group at -20 to 0 degrees C with three mole equivalents of n-BuLi in anhydrous THF. Reactions of the dilithium reagents produced in situ with various electrophiles give high yields of the corresponding substituted products. In the case of the urea, side-products due to lithiation and substitution on one of the methyl groups of the urea unit are obtained in low yields (0-17%).

• 出版日期2014-2