Organocatalytic Enantioselective 1,3‐Dipolar [6+4] Cycloadditions of Tropone

A highly stereoselective 1,3‐dipolar [6+4] cycloaddition towards bridged azabicyclo[4.3.1]decane scaffolds has been developed, reacting aldehydes, 2‐aminomalonates and tropone under mild conditions in the presence of a chiral phosphoric acid catalyst. The scope is demonstrated for a series of aldehydes and 2‐aminomalonates, and the reaction proceeds in high yields, >95:5 d.r. and up to 99 % ee. A series of transformations, as well as a mechanistic proposal, are presented. High on Tropone! A 1,3‐dipolar [6+4] cycloaddition of tropone and azomethine ylides is disclosed. The multicomponent reaction, leading to complex bridged architectures from simple starting materials, is catalyzed by a chiral phosphoric acid and displays high yields and stereoselectivities. Multiple stereoselective transformations show the synthetic utility of the obtained cycloadducts.