# Diastereodivergent and Enantioselective Organocatalytic Synthesis of Spiro-Fused Coumarins via [4+2] Cycloadditions

## TL;DR

Scientists developed a new method to create spiro-fused coumarins with high precision using organocatalysis and diastereodivergent control.

## Contribution

A novel organocatalytic method for enantioselective and diastereodivergent synthesis of spiro-fused coumarins via [4+2] cycloadditions.

## Key findings

- Trienamine-mediated Diels–Alder reactions with cyclic 2,5-dienones yield spiro-fused coumarin derivatives with high enantioselectivity.
- Reversible diastereoselectivity is achieved using cinchonidine-based amine with p-methylbenzoic acid or triethylamine.
- Electron-withdrawing groups at C3 of coumarins influence reactivity patterns and diastereodivergence.

## Abstract

A highly enantioselective,
organocatalytic, diastereodivergent
synthesis of spiro-fused coumarin derivatives via trienamine-mediated
Diels–Alder reactions with cyclic 2,5-dienones is reported.
Using a cinchonidine-based primary amine and either p-methylbenzoic acid or triethylamine enables reversible diastereoselectivity,
providing complementary enantioenriched diastereoisomers. The influence
of electron-withdrawing groups at C3 of coumarins is delineated, revealing
distinct reactivity patterns. Computational studies provide insight
into the mechanism and additive-controlled diastereodivergence.