Stabilized Nucleophiles with Electron Deficient Alkenes and Alkynes

摘要: The addition of stabilized nucleophiles to activated π-systems is one the oldest and most useful constructive methods in organic synthesis, dating back more than a hundred years. In 1887 Michael, after whom well-known example this reaction was named, published first series papers on describing sodium salt both diethyl malonate (1) ethyl acetoacetate (2) cinnamate (3) give products (4) (5), respectively (equation 1).1 This Michael reaction, which carbanion by or usually two electron-withdrawing groups adds β-carbon an α,β-unsaturated carbonyl derivative, represents earliest highly utilized for carbon–carbon bond formation. that same paper,1a also reported synthesis triethyl cyclopropane-1,1,2-tricarboxylate (9) from α-bromoacrylate (6) via intermediates (7) (8), synthetic route cyclopropanes used often today (Scheme 1). 1894 he showed alkynic ester could function as electrophilic component these reactions, e.g. (10a) (10b) giving (11a) (11b), 2).2 its variants were wide use around turn century prepare straight chain polycarboxylates, (12) (13; equation 3) cyclohexane-1,3-diones, (15; 4) (via Knoevenagel Claisen condensations).3 combination followed intramolecular aldol condensation decarboalkoxylation furnishes cyclohexenones, isophorone (17; 5), enones such mesityl oxide (16) (2).4 process annulation made much general 1930s Robinson his coworkers,5 who vinyl ketones their derivatives, Mannich bases, be with simple ketone enolates produce cyclohexenones variety, (20; 6), has come known annulation.6