In the pursuit of creating macromolecules with controlled molecular weight, sequence, and end groups, condensation polymerization remains an underexploited synthetic tool because of its intrinsic step-growth nature. Introducing chain-growth pathways into condensation polymerization calls for highly efficient chemistries that effect the challenging differentiation between functional groups of the same type present in monomers and polymers. Here, we address this challenge by a catalyst bifurcation strategy that enables a copper-catalyzed chain-growth condensation polymerization. Using a copper(I) arylacetylide as an initiator/precatalyst along with a phosphine ligand, polydiynes of controllable molecular weights and end groups are synthesized from readily available propargyl carbonates, including a block copolymer. This method provides a new chain-growth access to functional acetylenic polymers, a class of useful materials that have been obtained essentially by step-growth methods to date. This work demonstrates the power of dual-role transition metal catalysis in accomplishing unusual selectivity in organic synthesis.

中文翻译：

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铜催化的炔丙基亲电体的链增长缩聚

在追求制造具有可控制的分子量，序列和端基的大分子时，缩聚反应由于其固有的逐步增长性质而仍未被充分利用。将链增长途径引入缩聚反应需要高效的化学方法，以实现单体和聚合物中相同类型的官能团之间具有挑战性的区分。在这里，我们通过使铜催化的链增长缩聚反应得以实现的催化剂分叉策略来应对这一挑战。使用芳基乙炔化铜（I）与膦配体一起作为引发剂/预催化剂，可从容易获得的碳酸炔丙酯（包括嵌段共聚物）合成分子量和端基可控的聚二炔。该方法为功能性炔属聚合物提供了一种新的链增长途径，这是迄今为止基本上已通过逐步增长方法获得的一类有用材料。这项工作证明了双重角色过渡金属催化在完成有机合成中异常选择性方面的强大能力。