Core‐Shell Functionalized Block Copolymer Micelles: A Versatile Approach Toward One‐Pot Two‐Step Tandem Reactions

Tandem reactions have received considerable attention in the past as an economic and ecological advantageous approach to carry out multi‐step reactions. The use of non‐compatible catalysts and which methods can be used to spatially separate them remains a major challenge. Here, we present a simplified approach to facilitate tandem reactions based on diblock copolymer micelles where the hydrophilic shell is functionalized with sulfonic acid groups and the micellar core contains l ‐proline as a second organo catalyst. Self‐assembly in water leads to block copolymer micelles that support a tandem reaction of a sulfonic acid catalyzed acetal cleavage in the micellar shell followed by a l ‐proline catalyzed aldol reaction in the micellar core. Three block copolymers were prepared with different ratios of SO 3 H and l ‐Proline groups within one block copolymer. Conversion of more than 95% for each reaction step and a syn / anti ratio of >3/97 with high enantiomeric excess (>95% ee) for the aldol product were achieved for the best block copolymer micelle. Moreover, the polymer micelles could be recycled in four consecutive runs and gave conversions of up to 98% for the acetal cleavage and 57% for the aldol reaction and proceeded with good enantio‐ (79% ee) and diastereoselectivity ( syn/anti = 4:96) in the 4 th run.