Rhodium‐Catalyzed Chemo‐, Regio‐, Diastereo‐, and Enantioselective Intermolecular [2+2+2] Cycloaddition of Three Unsymmetric 2π Components

Abstract

We have developed the Rh + /H 8 -binap-catalyzed chemo-, regio-, diastereo-, and enantioselective intermolecular [2+2+2] cycloaddition of three unsymmetric 2π components. Thus, two arylacetylenes react with a cis-enamide to yield a protected chiral cyclohexadienylamine. Moreover, replacing one arylacetylene with a silylacetylene enables the [2+2+2] cycloaddition of three distinct unsymmetric 2π components. These transformations proceed with excellent selectivity (complete regio-and diastereoselectivity and up to > 99 % yield and > 99 % ee). Mechanistic studies suggest the chemo-and regioselective formation of a rhodacyclopentadiene intermediate from the two terminal alkynes.

Chemoselective [2 + 2]/[3 + 2] Photocycloaddition of 1,4-Dihydropyridines: Experimental and Theoretical Investigation

“…Photocycloadditions are widely used in organic synthesis in which two molecules combine to form a cyclic compound under the irradiation of light, including [2 + 2] photocycloadditions, [2 + 2 + 2] photocycloadditions, [3 + 2] photocycloadditions, and so on . The specific type of photocycloaddition depends on the characteristics of the reactants and the reaction conditions.…”

Regio- and stereo-selective synthesis of β-phenylthio enamidesviaintramolecular 1,2-thiol migration

“…Enamide 5b is well known as a versatile reactant, which could be applied for further transformation. 18…”

Concise synthesis of succinimide-fused 1,3-cyclohexadienes via Co-catalyzed [2 + 2 + 2] cycloaddition of 1,6-diynes and maleimides

“…Similarly, this strategy can be used to build 1,3-cyclohexadiene motifs by deploying alkynes and alkenes as cycloaddition components. Among the methods reported for synthesizing such skeletons via intermolecular or intramolecular [2 + 2 + 2] cycloaddition of alkynes and alkenes (Scheme 1a), 2 those involving noble metals, which usually exhibit good reactivity, have been extensively investigated. Comparatively, the assembly of 1,3-cyclohexadiene derivatives under the catalysis of earth-abundant metals has hardly been investigated.…”