Detailed Mechanistic Pattern in Halogen Dance Reactions of Iodothiophenes

Background: Synthetic chemists have utilized base catalyzed halogen dance reactions ever since their discovery by Bunnet et al. Many modifications under various conditions have en-abled synthetic chemists to build substituted heterocyclic targets with rich structural diversity. Methods: Using DFT-Cam-B3LYP/ land2dz computations and focusing on Hannes Frohlich et al. Halogen dance reactions of iodothiophenes, a new iodo-bridged transition state is proposed. This io-do-bridged TS was then used to put forth 8 possible isomerization as well as 8 possible dispropor-tionation paths. Results & Discussion: All mechanistic pathways were then thoroughly investigated based on TS's energy and protonation/deprotonation steps to find the most suitable pathways. Collectively, these mechanistic pathways were joined like a jigsaw puzzle to yield, for the first time, a comprehensive cascade-like pattern for base-catalyzed halogen dance in iodothiophenes. Conclusion: The present work may shed light on a dynamic domino mechanism that may well dominate the organic chemistry of iodothiophenyl anions. Trends like this may reveal mechanistic pathways in base digestion of halogenated aromatic compounds in CS2.