Michael Addition of N-Unprotected 2-Oxindoles to Nitrostyrene Catalyzed by Bifunctional Tertiary Amines: Crucial Role of Dispersion Interactions
作者:Christoph Reiter、Sònia López-Molina、Bernhard Schmid、Christian Neiss、Andreas Görling、Svetlana B. Tsogoeva
DOI:10.1002/cctc.201301052
日期:2014.3.5
Bifunctional thiourea‐ or sulfonamide‐derived tertiary amines catalyze the enantioselective nitro‐Michael addition of N‐unprotected 3‐substituted 2‐oxindoles to nitrostyrene in up to 99 % yields, 94:6 er, and 87:13 dr. Overcoming the necessity to introduce and remove activating or protecting groups at the nitrogen moiety leads to a reduction of energy use, costs, and waste. Transition‐state geometries
双官能硫脲或磺酰胺衍生的叔胺可催化将N-未保护的3-取代的2-氧吲哚的对映体选择性硝基-迈克尔加成至硝基苯乙烯中,产率高达99%,94:6 er和87:13 dr。克服了在氮部分上引入和除去活化或保护基的必要性,导致能源使用,成本和浪费的减少。计算了由竹本叔胺-硫脲催化的N-未保护的3-取代的2-氧吲哚的硝基-迈克尔加成到硝基苯乙烯中的所有可能的立体异构体形成的过渡态几何。结果表明,反应物与催化剂分子的相对位置和结合方式很大程度上取决于范德华相互作用。