Metal-Free Access to Fully Substituted Skipped Diynes. An Efficient Chemodifferentiating A2BB‘ 4CR Manifold
摘要:
A metal-free chemodifferentiating A(2)BB' 4CR manifold for the modular synthesis of tertiary skipped diynes is described. The manifold performs a triethylamine triggered reaction of alkyl propiolates and acid chlorides to assemble two units of each component in the form of two propargylic alkynoates, a tertiary alcohol, and an ester. A differentiated incorporation of the two acid chloride components ensures functional diversity in the final structure. In addition, the presence of two connected propargylic alkynoates provides a reactive platform for complexity generation.
Privileged scaffolds: Breaking the symmetry of 1,4‐diyne scaffolds by nucleophilic amine addition onto one of two equivalent alkynoate units affords chain‐functionalized tetrasubstitutedpyrroles with five points of functional diversity and two points for complexity generation. The domino reaction manifold entails an aza‐Michael addition, a 5‐endo‐digonal cyclization, and a [3,3]‐sigmatropic rearrangement