Recent Advances in Palladium‐Catalyzed Cycloadditions Involving Trimethylenemethane and its Analogs

Palladium-Catalyzed Highly Stereoselective Dearomative [3 + 2] Cycloaddition of Nitrobenzofurans

“…Notably, 1i with an ester group and 1j with a nitro group were tolerated, indicating a broad scope of this reaction. Furthermore, benzofurans with substituent at the 6 or 7 position bearing groups with varied electronic properties (6-MeO, 6-Br, 6-Ph, 6-phenylethynyl, 7-MeO, 7-Me, 7-allyl) were converted successfully in good to excellent yields and selectivity ( Table 2, entries [11][12][13][14][15][16][17]. Alkene and alkyne were also integrated under these reaction conditions ( Table 2, entries 14 and 17).…”

“…Palladium-catalyzed formal [3 + 2] cycloaddition reaction [10][11][12] between electrondeficient alkenes and epoxybutenes 13 is a powerful and atom-economic tool for the synthesis of substituted tetrahydrofurans. [14][15][16][17][18][19][20][21] Unfortunately, control of the enantioselectivity and diastereoselectivity of this kind of reaction remains challenging because of the long distance between the reactive site and the chiral catalyst in the stereoselectivity-determining transition state.…”

Development of an Asymmetric Trimethylenemethane Cycloaddition Reaction: Application in the Enantioselective Synthesis of Highly Substituted Carbocycles

“…1 Utilization of Pd-TMM complexes derived from 3-acetoxy-2-trimethylsilylmethyl-1-propene ( 1 ) has resulted in the efficient catalytic syntheses of carbocycles 2 and heterocycles. 3 Although this methodology was disclosed over thirty years ago by our laboratory 4 , a general asymmetric variant of the cycloaddition remained elusive until 2006.…”

Enantioselective Palladium-Catalyzed [3 + 2] Cycloadditions of Trimethylenemethane with Nitroalkenes

“…1 First described over 30 years ago as a racemic method, 2 a general, asymmetric protocol was only recently achieved with the discovery that phosphoramidites bearing bulky 2,5-diarylpyrrolidines were effective chiral ligands. 3a Using these ligands, we have demonstrated asymmetric [3+2] cycloadditions with several olefins, 3 imines 4 and aldehydes.…”