Enamino ketone variant of the Robinson annelation

Alkylations of Enols and Enolates

“…ate gave mainly the (S)-alkylated .system. Esters of the type (136) and (137) derived from benzyl-protected glycolates were found to yield (E)-enolates both in the absence and presence of HMPAu The (E)enolate of a chiral propionate ester derived from 10-sulfonamidocamphor was diastereoselectivity alkylated from the si-face. 252…”

Finding Lead Catalytic Systems for a Rare Version of Enantioselective Robinson Annulation: Integration of Fluorogenic Assays in Catalyst Screening

“…The results demonstrated a complete lack of activity for all tested amines but pyrrolidine (12% yield), unequivocally pointing to pyrrolidine as the only possible catalytic candidate. 22 Noticeably, in one of the rare publications reporting this variant of the annulation for more reactive chalcones, 9b pyrrolidine was the most reactive amine catalyst, among those examined. Taking into account that in the above-described case of polymer-supported catalysis the activity of the system was boosted up by benzoic acid, in the subsequent series of experiments, various acidic additives were used in the model reaction catalyzed by pyrrolidine (Table 5).…”

“…A set of potentially catalytic primary and secondary amines was, therefore, used as homogeneous catalysts in the fluorogenic model reaction of (NMe 2 ,H)-chalcone with acetone (Scheme and Table ), initially without any acidic cocatalyst. The results demonstrated a complete lack of activity for all tested amines but pyrrolidine (12% yield), unequivocally pointing to pyrrolidine as the only possible catalytic candidate . Noticeably, in one of the rare publications reporting this variant of the annulation for more reactive chalcones, pyrrolidine was the most reactive amine catalyst, among those examined.…”

Bromomalonates as synthetic reagents. Transfer alkylations

“…3.64 (s, COOCH3), 5.23 (s, COOCH3), 7.80 (dd, one proton of methylene, 7=10 and 7.3 Hz), 8.01 (dd, one proton of methylene, J = 9 and 4.5 Hz), 9.31 and 9.41 (d, both POOCH3, 7=11 Hz), and 10.94 (ddd, methine, J = 25, 10.5, and 4.25 Hz); mass spectrum m/e (rel intensity) 254 (3), 223 (100), 195 (95), 163 (89), 113 (55), 110 (40), 109 (58), 93 (48), 59 (25), and 55 (52). Anal.…”

“…and 294 mg ( I .48 mmol) of methyl 3-carbomethoxy-3,5-heptadienoate (9) was added dropwise. A solution oT 240 pI ( l .7 l mmol) of diisbpropylamine in 7 ml of dry tetrahydrofuran was cooled to -20 OC followed by the dropwise addition of 1 ml (1.6 mmol) of a 1.6 M solution of n-butyllithium in hexane.…”