A Facile Synthesis of .gamma.-Lactams and Secondary Amines from Conjugated Dienes and Imines

Abstract

y-Lactams are important intermediates in synthetic routes to five-membered heterocyclic compounds. Moreover, tetramic acids and 3-pyrrolin-2-ones represent a diverse and profoundly important family of biologically active secondary metabolites, many of which have potential use in both medicine and agriculture.1 Synthetic interest in this class of molecules has been intense, particularly in the past decade.2

The First I2-Promoted Efficient Aminoacetylation of Activated Aziridines in Ionic Liquid

“…[4][5][6][7][8] Due to their versatile applications in organic and medicinal chemistry, the development of new synthetic routes for the preparation of pyrrolidin-2-ones is an important endeavor and has been well documented in the literature. [10][11][12][13][14][15][16][17][18][19][20][21] However, most of the reactions suffer from one or more disadvantages, such as expensive reagents, long reaction times, low yields, tedious workup, and, most importantly, none of these methods cater a direct process for the synthesis of 3-(N-substituted)aminopyrrolidin-2-ones and tend to be lengthy and cumbersome if the lactam contains any sort of substitution. Recently, Ghorai et al have reported the synthesis of pyrrolidin-2-one via a nucleophilic ring opening with a methylene group 22a in addition to other literature reports on the synthesis of 4-(N-substi-tuted)aminopyrroildin-2-ones.…”

Direct Synthesis of Spiro .delta.-lactones, Spiro-.gamma.-Lactones, and Alcohols from Substituted (2-Butene-1,4-diyl)magnesium Complexes

“…Caled: C, 76.94; H, 9.47. Found: C, 76.58; H, 9.34. 6-Butyltetrahydro-4-methyl-4-(l-methylethenyl)-2ffpyran-2-one (13): 72% yield (1:1 mixture of diastereomers); NMR ó 4. 93-4.77 (m, 4H), 4.41-4.39 (m, 1H), 4.20-4.10 (m, 1H), 2.86-2.78 (m, 1H), 2.50-2.45 (m, 2H), 2.27-2.20 (m, 1H), 2.05-1.97 (m, 1H), 1.86-1.77 (m, 1H), 1.75-1.72 (m, 6H), 1.71-1.25 (m, 14H), 1.24-1.17 (s, 3H), 1.16-1.12 (s, 3H), 0.95-0.85 (m, 6H); 13C NMR ó 171.8,171.5,150.4, 147.7, 112.1, 109.4, 77.7, 77.2, 42.0, 41.3, 39.2, 39.0, 38.3, 37.4, 36.5, 35.7, 35.4, 27.8, 27.0, 26.9, 24.6, 22.5, 22.4,18.9,18.8,13.8;IR (neat) 3087, 2956IR (neat) 3087, , 2931IR (neat) 3087, , 2871IR (neat) 3087, , 1735IR (neat) 3087, , 1639IR (neat) 3087, , 1455IR (neat) 3087, , 1380 6-Ethyltetrahydro-4-methyl-4-(l-methylethenyl)-2Ffpyran-2-one ( 14): 58% yield (1:1 mixture of diastereomers); NMR ó 4.…”

“…High regioselectivity in the attack of unsymmetrically substituted epoxides was also realized. The formation of a ¿-substituted ¿-lactone, 6-butyltetrahydro-4-methyl-4-(l-methylethenyl)-2£f-pyran-2-one (13) in 72% isolated yield (Table 1, entry 5), illustrates that the attack by the diene-magnesium complex of 1,2-epoxyhexane ocurred at the less sterically hindered carbon. Synthetic routes to ¿-substituted ¿-lactones are important because molecules of this class include many natural products that reveal significant biological activity.19 For other examples of this regioselective attack of unsymmetric epoxides, see Table 1 (entries 6-8).…”

Al Atom Activation of C–S Bonds: Characterization of the Aluminathietane Formed in the Reaction of Al Atoms with 1,2-Butylene Sulfide

“…For example, γ-lactams 2 were synthesized by reacting imines with substituted magnesacyclopentene intermediates in the presence of carbon dioxide, while their hydrolysis yielded secondary amines. 2 The magnesacyclopentene intermediates resulting from the reaction of substituted 1,2-bis(methylene)cyclohexane with activated magnesium were found to be very versatile in that they were easily converted to substituted cyclopentanols, fused-ring cyclopentanols, β,γ-unsaturated ketones, 3 and γ-lactones. 4 Epoxides add to the magnesacyclopentene intermediate to give 7-methylene-2magnesa-3-oxaspiro [5.5]undecane, which can in turn be transformed into a primary alcohol containing a quaternary center upon acid hydrolysis.…”