Palladium-catalyzed ortho-olefination of 2-arylpyrrolidines: A tool for increasing structural complexity in nitrogen heterocycles
作者:Pablo D. Legarda、Alfonso García-Rubia、Ramón Gómez Arrayás、Juan C. Carretero
DOI:10.1016/j.tet.2018.05.076
日期:2018.7
of the (2-pyridyl)sulfonyl unit as directing functionality and readily removable N-protecting group has enabled an efficient and practical transformation of 2-arylpyrrolidine derivatives into more complex tricyclic frameworks via palladium-catalyzed ortho-olefination with electron deficient alkenes and subsequent cyclization upon N-deprotection under mild conditions. The key cross coupling step in the
(2-吡啶基)磺酰基单元作为直接官能团和易于除去的N-保护基团的双重作用使得能够通过钯催化的与缺电子烯烃的邻位烯烃化反应将2-芳基吡咯烷衍生物有效而实用地转化为更复杂的三环骨架。和随后在温和条件下在N-脱保护下环化。在三氟甲磺酸N-氟-2,4,6-三甲基吡啶鎓([F +])的存在下,关键的交叉偶联步骤既高效又可耐受两个偶联伙伴处的各种空间和电子变化。通过的还原条件适当选择,Ñ-磺酰基脱保护基可以选择性地形成苯并-稠合的吡咯烷或稠合的吡咯烷基-苯并氮杂framework骨架。