Asymmetric Diels–Alder cycloadditions of benzofulvene-based 2,4-dienals via trienamine activation

Abstract

A new type of 2,4-dienal featuring a benzofulvene skeleton is utilised in asymmetric Diels–Alder cycloadditions with 3-olefinic oxindoles via trienamine catalysis.

Polyenals and Polyenones in Aminocatalysis: A Decade Building Complex Frameworks from Simple Blocks

“…Herein, benzofulvenes 15 as 2,4‐dienals were shown to react with dienophile 16 via trienamine intermediates. Through this strategy, a library of polyhydrofluorenes 17 was generated with high level of regio‐ and enantioselectivities in moderate to high yields (Scheme ) …”

Electron-rich benzofulvenes as effective dipolarophiles in copper(i)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides

“…Benzofulvenes, a kind of synthon having semi-aromatic characteristics, have been mainly employed in the synthesis of polymeric compounds and transition-metal-complexes. 11 In comparison, the utilization of these synthons to construct small molecules was rarely reported, particularly in a catalytic asymmetric manner, 12 which may be ascribed to the low activity of the diene in the benzofulvene. In 2016, Jørgensen introduced an electron-withdrawing group at the 3-position of the benzofulvene to enhance the reactivity of the exocyclic double bond, which served as a 2π-component to react with 2,4-dienals or dimethyl bromomalonate in the presence of chiral catalysts.…”

Complementary C–H Functionalization Mode of Benzoylacetonitriles: Computer-Augmented Study of a Regio- and Stereoselective Synthesis of Functionalized Benzofulvenes

“…Recent studies identified a number of benzofulvene-containing natural products with remarkable biological and pharmaceutical potential . In addition, functionalized benzofulvenes are also versatile building blocks widely used among the synthetic community …”