分子内アルキル転位反応を用いるインドール誘導体の合成

抄録

An intramolecular 1,2-alkyl migration from boron to carbon in trialkylalkenylborate has been well defined as a useful protocol for carbon–carbon bond formation. We have embarked upon extending the scope of this migration process in indolylborates to an intramolecular cyclization enabling the one-pot construction of [a]- and [b]-annelated indole derivatives from the corresponding indoles. During these studies, it was found that the alkyl migration reaction in 1-methoxymethylindolylborates led to 1-methyl-2-alkylindoles, in which the intermediary formation of alkylboranes through a novel cascade of alkyl-boryl migration steps was taken as the key reaction feature.

Scheme 1