Preparation of Functionalized Diaryl- and Diheteroaryllanthanum Reagents by Fast Halogen-Lanthanum Exchange
作者:Andreas D. Benischke、Lucile Anthore-Dalion、Guillaume Berionni、Paul Knochel
DOI:10.1002/anie.201709553
日期:2017.12.18
Aryl and heteroaryl halides (X=Br, I) undergo a fast and convenient halogen–lanthanum exchange with nBu2LaMe, which leads to functionalized diaryl‐ and diheteroaryllanthanum derivatives. Subsequent trapping reactions with selected electrophiles, such as ketones, aldehydes, or amides, proceeded smoothly at −50 °C in THF, affording polyfunctionalized alcohols and carbonyl derivatives. Kinetic competition
芳基和杂芳基卤化物(X = Br,I)与nBu 2 LaMe进行快速便捷的卤素-镧交换,这导致官能化的二芳基和二杂芳基镧衍生物。随后与选定的亲电子试剂(如酮,醛或酰胺)的捕集反应在-50°C的THF中顺利进行,得到多官能化的醇和羰基衍生物。动力学竞争实验显示出与Br / Mg交换相似的反应趋势,但速率提高了10 6倍,使其与Br / Li交换相当。