Stereoselective cyclohexadienylamine synthesis through rhodium-catalysed [2+2+2] cyclotrimerization

Steric Parameterization Delivers a Reciprocally Predictive Model for Substrate Reactivity and Catalyst Turnover in Rh-Catalyzed Diyne-Alkyne [2 + 2 + 2] Cycloadditions

“…The related [2 + 2 + 2] cycloadditions involving nitriles (to yield pyridines) and alkenes (to yield cyclohexadienes) expand this overall area and enable access to an increased diversity of scaffolds. 16,17 Overall this general reaction class has been extensively deployed within the synthetic strategy, including natural product and pharmaceutical synthesis, and polymerization. 2−12 The Rh-catalyzed diyne-alkyne process, in particular, has seen the significant application.…”

“…Completely intermolecular cycloadditions using three different alkynes are very difficult, due to issues with simultaneous control of both chemo- and regioselectivity; however, tethering methods have offered a specific solution to this problem. , The diyne-alkyne process offers the most modular approach and has therefore seen significant interest in methodological development. The related [2 + 2 + 2] cycloadditions involving nitriles (to yield pyridines) and alkenes (to yield cyclohexadienes) expand this overall area and enable access to an increased diversity of scaffolds. , Overall this general reaction class has been extensively deployed within the synthetic strategy, including natural product and pharmaceutical synthesis, and polymerization. − …”

Stereoselective synthesis of [2.2]triphenylenophanesviaintramolecular double [2 + 2 + 2] cycloadditions

“…3c). 27,28 We found that the activation energy for the rate-limiting vemembered rodacycle formation [(Rp,Sa)-IM0 / IM1 / TS1, DG ‡ = 19.1 kcal mol −1 ] is more than 6 kcal mol −1 larger than the rotational isomerization between (Rp,Sa)-IM0 and (Rp,Ra)-IM0. Thus we can conclude that the second [2 + 2 + 2] cycloaddition kinetically determines the diastereoselectivity.…”

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

“…[7] In 2022, our group reported the chiral cationic rhodium-(I)-catalyzed asymmetric [2+2+2] cycloaddition [10] of two distinct alkynes [terminal alkynes and symmetric electronpoor internal alkynes (dialkyl acetylenedicarboxylates)] with a cis-enamide with excellent chemo-, regio-, diastereo-, and enantioselectivity (Scheme 1c, top). [8,9] A wide range of terminal alkynes was applicable, but the symmetric electronpoor internal alkynes were essential to maintain high chemo-and regioselectivity. Thus, no reaction was observed in the absence of the dialkyl acetylenedicarboxylate (Scheme 1c, middle), and using unsymmetric electron-deficient internal alkynes required excess silylacetylenes (5 equiv) and almost always resulted in a mixture of regioisomeric products (Scheme 1c, bottom).…”