[8+2]‐Cycloaddition Reaction of Carbamates and N‐Sulfonyl azaheptafulvenes

Abstract

The base‐mediated higher‐order [8+2]‐cycloaddition reaction of carbamates with N‐sulfonyl azaheptafulvenes has been successfully developed, providing a facile access to a series of highly functionalized cycloheptatriene‐fused imidazolidin‐2‐one derivatives in 52–95 % yields. This reaction features transition‐metal free, simple operation, and mild reaction conditions. Additionally, this transformation can also be utilized to modify some natural isolates.

Lewis base-catalyzed cascade [4 + 2]-annulation reaction of N-alkoxy acrylamides and acyl isothiocyanates: facile access to 2-imino-1,3-thiazinone derivatives

“…Thus, the potential applications of N -alkoxy acrylamides still need to be further explored. As a continuation of our research focusing on the construction of N -containing heterocycles, 20 we report a Lewis base-catalyzed cascade [4 + 2]-annulation reaction of N -alkoxy acrylamides and acyl isothiocyanates in this work. This reaction leads to the formation of highly functionalized 2-imino-1,3-thiazinone derivatives (Scheme 2c).…”

Synthesis of Polycyclic Imidazolidinones via Cascade [3 + 2]-Annulation of β-Oxo-acrylamides with Cyclic N-Sulfonyl Imines

“…On the other hand, cyclic N -sulfonyl imines exhibit versatile reaction activity in organocatalytic, metal-catalyzed, or radical-mediated cycloaddition reactions, which provide straightforward, powerful, and atom-economical methods to a wide range of diverse pharmacologically sultam or sulfamidate-fused nitrogen-containing heterocycles . Based on our achievements in the field of heterocyclic chemistry involving N -alkoxy α-halohydroxamate or acrylamide, and in line with our continuous efforts in annulation reactions, we have successfully established an Et 3 N-catalyzed aza-Mannich reaction triggered cascade annulation reaction of β-oxo-acrylamides with cyclic N -sulfonyl imines, leading to the formation of highly functionalized sulfamide-fused imidazolidinone derivatives (Scheme f). Meanwhile, we also studied the asymmetric [3 + 2]-cycloaddition reaction using chiral bifunctional squaramide organocatalysts.…”