Cycloaddition Reactions of Enamines

Abstract

This review includes information for around two last decades on cycloaddition reactions of enamines with various agents in order to build carbo‐ and heterocycles. In addition, the review presents organo‐catalytic reactions in which enamines are intermediate products generated in situ. This review covers the synthesis of four, five, six and eight‐membered carbocyclic compounds, as well as heterocycles as pyrroles, pyridines, etc.

Lewis Acid‐Driven Inverse Hydride Shuttle Catalysis

“…Inverse hydride shuttle catalysis harvests the well‐known, but little exploited, formal [2+2] cycloaddition of enamines and Michael acceptors, [17] leveraging the cyclobutane products in a unique rearrangement event. Acrylates are some of the most common acceptors for reactions of this type [18] .…”

Lewis Säure‐Getriebene Inverse Hydrid‐Shuttle Katalyse

“…Inverse Hydrid‐Shuttle Katalyse bedient sich der bekannten, aber wenig genutzten, formalen [2+2]‐Cycloaddition von Enaminen mit Michael‐Akzeptoren, [17] indem die Cyclobutanprodukte in eine einzigartige Umlagerung involviert werden. Acrylate gehören hierbei zu den am häufigsten verwendeten Akzeptoren für solche Reaktionen [18] .…”

A Neutral PCNHCP Co(I)–Me Pincer Complex as a Catalyst for N-Allylic Isomerization with a Broad Substrate Scope

“…1a,d,2a,3 By contrast, double bond migration from an N-allyl motif has been underrepresented in the literature despite its presence in a variety of natural products, agrochemicals, and industrially relevant compounds. 3a,4 The isomerization of N-allylic framework enables a selective and atom-economical pathway to highly polarized N-(1propenyl) or generally N-vinyl intermediates, 3a whose enamines, enamides, and aza-dienes are commonly used in cycloadditions, 5 cyclopropanations, 6 heterocycle synthesis, 7 halofunctionalizations, 8 and transition-metal-catalyzed C−C bond-forming reactions. 9 In addition, the transition-metal catalyzed tandem isomerization of N-allylic double bonds followed by functionalization of the in situ formed N-vinyl intermediate offers access to functionalized molecules that would be difficult to synthesize otherwise.…”