A density functional theory (DFT) study has been carried out to provide insight into the reaction mechanism of the rhodium(I)-catalyzed, P-directed selective C7 arylation of indoles with aryl halides. Our calculations suggest that it is more favorable for Rh(PPh₃)₂O^tBu, the real catalytical species for the reaction, to initially undergo C–H activation process with the indole to generate a five − membered rhodacycle intermediate than to proceed through oxidative addition with the aryl halide to yield a Rh(III) intermediate. Subsequently, the sequential C(aryl)−C(aryl) reductive elimination and catalyst regeneration progresses produce the final 7−arylindole product. The first C–H activation process is identified as rate- and regioselectivity-determining step with an energy barrier of 26.0 kcal/mol. The underlying origins and factors responsible for C7- vs C2-, C3-, and C6-regioselectivity is revealed by noncovalent interaction analysis. The results declare that the reaction characters weak interaction and chelate effect-controlled regioselectivity. Our study provides important mechanistic insights for the dehydrogenative cross-coupling reaction between indoles with aryl halides, and guides the design of efficient Rh-based catalyst for C–H functionalization of indoles.

进行了密度泛函理论（DFT）研究，以提供有关铑（I）催化的吲哚与芳基卤化物的P定向选择性C7芳基化反应的机理的见解。我们的计算表明，Rh（PPh ₃）₂ O ^t更有利Bu是反应的真正催化物质，最初会与吲哚发生CH–H活化过程，生成五元的Rhodacycle中间体，然后再与芳基卤化物进行氧化加成反应，生成Rh（III）中间体。随后，顺序的C（芳基）-C（芳基）还原消除和催化剂再生进行，产生最终的7-芳基吲哚产物。第一个C–H活化过程被确定为决定速率和区域选择性的步骤，其能垒为26.0 kcal / mol。非共价相互作用分析揭示了引起C7-与C2-，C3-和C6-区域选择性的潜在起源和因素。结果表明，反应特性弱相互作用，螯合效应控制区域选择性。