Efficient Synthesis of Dispiropyrrolidines Linked to Sugars

Abstract

An expedient method for the synthesis of glyco-dispiropyrrolidines is reported through 1,3-dipolar cycloaddition reaction (1,3 DC reaction). The novel glycosyl dipolarophiles derived from D-glucose underwent neat [3+2] cycloaddition reaction with the azomethine ylides generated from 1,2-diketones and sarcosine to give the corresponding glycosidic heterocycles in good yields.

Nascent-HBr-Catalyzed Removal of Orthogonal Protecting Groups in Aqueous Surfactants

“…22 Colorless semisolid, 87% (228 mg); 1 H NMR (500 MHz, CDCl 3 ) δ (ppm): 5.91 (d,1H,J = 3.4 Hz),5.27 (br s,1H),4.60 (d,1H,J = 3.4 Hz),4.18 (dd,1H, J 1 = 2.6 Hz, J 2 = 9.0 Hz), 3.86 (dd, 1H, J 1 = 2.6 Hz, J 2 = 11.7 Hz), 3.73 (dd, 1H, J 1 = 6.3 Hz, J 2 = 11.7 Hz), 3.68−3.63 (m, 1H), 2.18 (s, 2H), 2.16 (s, 3H), 1.52 (s, 3H), 1.32 (s, 3H); 13 C{ 1 H} NMR (125 MHz, CDCl 3 ) δ (ppm): 171.2, 112.3, 104.8, 83.0, 79.1, 68.1, 64.0, 29.7, 26.5, 26.1, 20.6. 3-O-Benzyl-1,2-O-cyclohexylidene-α-D-glucofuranose (2e). 23 Colorless, viscous liquid, 95% (332 mg); 1 H NMR (500 MHz, CDCl 3 ) δ (ppm): 7.39−7.30 (m, 5H), 5.95 (d,1H,J = 3.5 Hz),4.74 (d,1H,J = 11.6 Hz),4.63 (d,2H, J = 3.1 Hz), 4.56 (ABq, 1H, J = 10.9 Hz), 4.14−4.10 (m, 2H), 4.03−3.97 (m, 1H) 128.8−127.2 (5C), 112.5,104.7,82.1,81.6,79.8,72.1,69.3,64.4,36.3,35.7,24.8,23.8,23.5. 2,.…”