Dative Directing Group Effects in Ti-Catalyzed [2+2+1] Pyrrole Synthesis: Chemo- and Regioselective Alkyne Heterocoupling was written by Chiu, Hsin-Chun;See, Xin Yi;Tonks, Ian A.. And the article was included in ACS Catalysis in 2019.Synthetic Route of C6H4BrIO This article mentions the following:
Transient dative substrate-Ti interactions have been found to play a key role in controlling the regioselectivity of alkyne insertion and [2+2] cycloaddition in Ti-catalyzed [2+2+1] pyrrole synthesis and Ti-catalyzed alkyne hydroamination. TMS-protected alkynes with pendent Lewis basic groups can invert the regioselectivity of TMS-protected alkyne insertion, leading to the selective formation of highly substituted 3-TMS pyrroles. The competency of various potential directing groups was investigated, and it was found that the directing-group effect can be tuned by modifying the catalyst Lewis acidity, the directing-group basicity, or the directing-group tether length. Dative directing-group effects are unexplored with Ti catalysts, and this study demonstrates the potential power of dative substrate-Ti interactions in tuning selectivity. In the experiment, the researchers used many compounds, for example, 4-Bromo-2-iodophenol (cas: 207115-22-8Synthetic Route of C6H4BrIO).
4-Bromo-2-iodophenol (cas: 207115-22-8) belongs to iodide derivatives. Organoiodine compounds occur widely in organic chemistry, but are relatively rare in nature. A typical method for synthesis of aromatic iodides is diazotization of primary aromatic amines followed by treatment of potassium iodide. Aliphatic alcohols are converted to alkyl iodides by treating with hydrogen iodide.Synthetic Route of C6H4BrIO
Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com