Catalytic Olefin–Imine Metathesis: Cobalt-Enabled Amidine Olefination with Enaminones

Abstract

Organic metathesis reactions allow for expedient assembly of diverse molecular skeletons and appendages through the exchange of molecular fragments. The olefin−imine variant of this process, in particular, can expand the synthetic toolbox for manipulating carbon−carbon and carbon−nitrogen bonds but has thus far been achieved only on a stoichiometric metal-mediated basis. Herein, we report the development of a catalytic olefin− imine metathesis reaction, featuring cobalt-catalyzed amidine olefination with enaminones and a versatile product synthon enabling further structural diversification.

A Tandem Regiospecific [3 + 2] Annulation/Ring Cleavage Reaction for the Synthesis of β-Ketoenamides

“…1 H NMR (400 MHz, CDCl 3 ): δ 10.44 (br s, 1H), 8.06–7.98 (m, 2H), 7.69–7.59 (m, 6H), 7.52–7.42 (m, 5H), 7.39–7.33 (m, 1H), 6.19 (s, 1H), 5.55 (br s, 1H). 1 H NMR spectral data are in good agreement with the literature data …”

“…1 H NMR spectral data are in good agreement with the literature data. 15 (Z)-3-Amino-1-(4-phenoxyphenyl)-3-phenylprop-2-en-1-one (3na). Yellow liquid, mp 75−77 °C, yield 37 mg, 59%, R f = 0.42 (PE/ EtOAc 5:1, v/v).…”

Electrochemical Enaminone-Thioamide Annulation and Thioamide Dimeric Annulation for the Tunable Synthesis of Thiazoles and 1,2,4-Thiadiazole

“…On the contrary, employing enaminone 1a along with the current conditions led to no enaminone dimerization, supporting that the reported reactions started from thioamide (see Scheme 6). 19 To investigate the plausible reaction mechanism, a series of mechanistic verification experiments were conducted, as shown in Scheme 5. First, we examined the reaction in the absence of H 2 SO 4 , and no desired product 3a was observed, suggesting that H 2 SO 4 played an important role in the reaction (Scheme 5a).…”

Hetero-ene Metathesis

“…Yet, for all of the power and versatility of olefin metathesis, it is inherently restricted to carbon–carbon double and triple bonds, which may not map onto valuable heteroatom-rich materials, including functional polymers, − biomacromolecules, dyes, and natural products (Figure B). , Synthesis of such materials could be dramatically streamlined and precisely controlled through metathesis of the corresponding heteroatom-containing double bonds (hetero-enes). Although some of these double bonds have been metathesized (e.g., carbonyls, − imines, − and carbodiimides − ), the catalysis and double bond scope (Figure C) have considerable room to improve. − From our perspective, these challenges are exciting opportunities to advance the young field of hetero-ene metathesis, in terms of both fundamental science and its applications.…”

“…Several examples of classes of heteroatom-rich compounds. C. Reported double bond metatheses. − If both catalyzed and uncatalyzed methodologies exist for a given functionality combination, then only the catalytic methodology is indicated.…”