An Approach to Cycloheptabindolesthrough an Allenamide (4 + 3) Cycloaddition–Grignard Cyclization–ChugaevElimination Sequence

摘要

A strategy for synthesizing highly functionalized cyclohepta[b]indoles through a concise (4 + 3) cycloaddition–cyclization–elimination sequence is described. The cycloaddition features nitrogen-stabilized oxyallyl cations derived from epoxidations of N-aryl-N-sulfonyl-substituted allenamides, while the cyclization and elimination employed an intramolecular Grignard addition and a one-step Chugaev process, respectively.