Combining Orthogonal Chain-End Deprotections and Thiol–Maleimide Michael Coupling: Engineering Discrete Oligomers by an Iterative Growth Strategy

Angewandte Chemie - International Edition

4 years ago

Combining Orthogonal Chain-End Deprotections and Thiol–Maleimide Michael Coupling: Engineering Discrete Oligomers by an Iterative Growth Strategy

Xiulin Zhu, Nianchen Zhou, Xiangqiang Pan, Xiaopeng Li, Fanying Meng, Zimu Wang, Junfei Zhao, Kunshan Ding, Zhengbiao Zhang, Zhihao Huang

Orthogonal maleimide and thiol deprotections were combined with thiol–maleimide coupling to synthesize discrete oligomers/macromolecules on a gram scale with molecular weights up to 27.4 kDa (128mer, 7.9 g) using an iterative exponential growth strategy with a degree of polymerization (DP) of 2n−1. Using the same chemistry, a “readable” sequence-defined oligomer and a discrete cyclic topology were also created. Furthermore, uniform dendrons were fabricated using sequential growth (DP=2n−1) or double exponential dendrimer growth approaches (DP=22n −1) with significantly accelerated growth rates. A versatile, efficient, and metal-free method for construction of discrete oligomers with tailored structures and a high growth rate would greatly facilitate research into the structure–property relationships of sophisticated polymeric materials. Discrete oligomers were fabricated by a versatile, efficient, and metal-free chemical process, which combines orthogonal deprotections of maleimide and thiol groups together with thiol–maleimide Michael coupling. Key: iterative exponential growth (IEG); double exponential dendrimer growth (DEDG); degree of polymerization (DP).

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/anie.201706522