Cascade approach to synthesize BIMs and analogues in different nucleophilic conditions

[Display omitted] •Synthesis of symmetrical BIMs via cascade strategy.•First ever application of Organometallic in synthesis of BIMs.•Reductive nucleophilic approach to access BIMs derivatives.•Milder, additive free, one component-one pot strategy.•Potential candidates for biological evolution. We report here a cascade synthetic approach to prepare 3,3′-bis(indolyl)methanes (BIMs) and analogues from single reactant 1H-indole-3-carbaldehydes under the reductive condition using NaBH4. Uniformly, in another strategy, 1H-indole-3-carbaldehydes produced BIMs as a cascade product under Grignard reaction conditions. This is the first application of organometallic and reductive nucleophilic condition, where indole-3-carbaldehydes underwent NaBH4 reduction/ methyl Grignard addition to form 1°/2° alcohol followed by elimination and subsequent addition of another molecule of indole aldehyde provided symmetric BIMs as unambiguous cascade products (22 analogues) in good to excellent yields.