An Approach to Pancratistatins via Ring‐Closing Metathesis: Efficient Synthesis of Novel 1‐Aryl‐1‐deoxyconduritols F.

Abstract

An Approach to Pancratistatins via Ring-Closing Metathesis: Efficient Synthesis of Novel 1-Aryl-1-deoxyconduritols F. -An efficient synthetic route to title compounds [cf. (VI)-(VIII)] from (I) is developed. A range of aromatic residues is incorporated in the cyclitol skeleton with total stereochemical control utilizing a diastereoselective aryl cuprate addition to a γ-alkoxy enoate. The multi-step sequence is optimized for the production of gram quantities of these compounds. - (NADEIN, O. N.; KORNIENKO*, A.; Org. Lett. 6 (2004) 5, 831-834; Dep. Chem., N. Mex. Inst. Min. Technol., Socorro, NM 87801, USA; Eng.) -Steudel 27-175

Intramolecular Tandem Seleno-Michael/Aldol Reaction: A Simple Route to Hydroxy Cyclo-1-ene-1-carboxylate Esters

“…20 The synthesis of compound 20 was completed in five steps from commercially available D-xylose in 69% overall yield. 21 Wittig reaction of the partially protected D-xylose 20 and ylide 21 gave a primary alcohol as a mixture of isomers (E/Z = 1:0.2) in 65% yield. Oxidation of the remaining primary hydroxyl group gave compound 17 after flash chromatography as a mixture of isomers (E/Z = 90:10) in 90% yield.…”

Synthesis of Phenolic Glycosides: Glycosylation of Sugar Lactols with Aryl Bromides via Dual Photoredox/Ni Catalysis

“…The crude residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc = 20:1 → 5:1) to afford 1. 8, 138.3, 137.9, 128.6, 128.6, 128.6, 128.5, 128.2, 128.2, 128.1, 128.1, 127.9, 127.9, 127.8, 97.9, 91.6, 83.3, 82.4, 79.6, 77.7, 77.6, 75.6, 74.9, 73.6, 73.4, 73.3, 63.9, 60.5;IR (in KBr) 3445, 3129, 3014, 1637, 1542 Hz, 2H), 3.66−3.56 (m, 4H), 3.36 (s, 1H), 2.73 (s, 1H), 1.33 (t, J = 7.5 Hz, 6H); 13 C NMR (100 MHz, CDCl 3 ) δ (ppm) 138. 7, 138.7, 138.4, 138.4, 138.2, 138.1, 128.8, 128.7, 128.5, 128.5, 128.4, 128.2, 128.2, 128.1, 128.1, 128.0, 127.9, 127.8, 127.8, 127.8, 127.7, 93.5, 93.1, 83.2, 80.6, 80.1, 79.8, 77.4, 76.7, 75.6, 75.5, 75.1, 75.0, 73.0, 72.4, 71.7, 68.3, 18.2, 18.1;IR (in KBr) 3445, 3129, 3030, 2928, 2341, 1453, 1094 Hz, 1.3H), 1.14 (d, J = 6.5 Hz, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ (ppm) 138.…”

“…8, 138.3, 137.9, 128.6, 128.6, 128.6, 128.5, 128.2, 128.2, 128.1, 128.1, 127.9, 127.9, 127.8, 97.9, 91.6, 83.3, 82.4, 79.6, 77.7, 77.6, 75.6, 74.9, 73.6, 73.4, 73.3, 63.9, 60.5;IR (in KBr) 3445, 3129, 3014, 1637, 1542 Hz, 2H), 3.66−3.56 (m, 4H), 3.36 (s, 1H), 2.73 (s, 1H), 1.33 (t, J = 7.5 Hz, 6H); 13 C NMR (100 MHz, CDCl 3 ) δ (ppm) 138. 7, 138.7, 138.4, 138.4, 138.2, 138.1, 128.8, 128.7, 128.5, 128.5, 128.4, 128.2, 128.2, 128.1, 128.1, 128.0, 127.9, 127.8, 127.8, 127.8, 127.7, 93.5, 93.1, 83.2, 80.6, 80.1, 79.8, 77.4, 76.7, 75.6, 75.5, 75.1, 75.0, 73.0, 72.4, 71.7, 68.3, 18.2, 18.1;IR (in KBr) 3445, 3129, 3030, 2928, 2341, 1453, 1094 Hz, 1.3H), 1.14 (d, J = 6.5 Hz, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ (ppm) 138. 8, 138.6, 138.3, 128.5, 128.5, 128.3, 128.3, 128.1, 128.0, 127.8, 127.8, 127.7, 127.7, 127.6, 97.8, 92.0, 82.6, 80.9, 79.2, 77.4, 77.4, 76.6, 76.5, 75.2, 74.9, 74.8, 73.6, 73.2, 73.1, 70.9, 66.8, 17.1, 16.9;IR (in KBr) 3367, 3131, 3032, 2935, 1453, 1365, 1140, 1106, 1054, 696 cm −1 ; HRMS (ESI-TOF) m/z [M + Na] + calcd for C 27 H 30 O 5 Na 457.1985Na 457. , found 457.1985.…”

“…2,3,6-Tri-O-benzyl-4-O-(2′,3′,4′,6′-tetra-O-benzyl-α-D-glucopyranosyl)-α/β-D-glucopyranoside (1j): α/β = 2:1, colorless oil; 1 H NMR (400 MHz, CDCl 3 ) δ (ppm) 27H),5H),2H),5.62 (d,J = 3.6 Hz,1H),5.22 (d,J = 3.6 Hz,0.7H),3H),3H),1H), 4.60−4.48 (m, 5.7H), 4.43 (dd, J = 10.8, 2.8 Hz, 1H), 4.32 (t, J = 12.4 Hz, 1H), 4.12 (d, J = 8.0 Hz,1H), 4.08−3.99 (m, 1.7H), 3.89 (dd, J = 16.0, 8.0 Hz, 1H), 3.84−3.71 (m, 2.7H), 3.69−3.61 (m, 3H), 3.57−3.39 (m, 3.7H), 3.09 (br, 0.7H); 13 C NMR (100 MHz, CDCl 3 ) δ (ppm) 138. 8, 138.7, 138.7, 138.4, 138.1, 138.0, 137.9, 137.9, 137.6, 128.5, 128.4, 128.4, 128.3, 128.3, 128.2, 128.2, 128.2, 128.1, 128.0, 127.9, 127.9, 127.8, 127.8, 127.8, 127.7, 127.7, 127.6, 127.6, 127.6, 127.5, 127.5, 127.2, 126.7, 126.6, 97.4, 97.0, 96.9, 90.8, 84.4, 83.1, 82.0, 81.4, 80.0, 79.4, 79.2, 77.6, 77.3, 75.6, 75.0, 75.0, 74.6, 74.3, 74.3, 73.9, 73.5, 73.3, 73.3, 73.2, 73.1, 72.9, 72.7, 71.2, 71.0, 69.8, 69.4, 69.1, 68 General Procedure for the Synthesis of Product 3.…”

“…4-Acetylphenyl 2,3,4,6-Tetra-O-benzyl-α/β-D-glucopyranoside (3aa): 107 mg, 81% yield, α/β = 8:1, white solid, mp 108−109 °C; [α] D 20 +96.6 (c 1.0, CHCl 3 ); 1 H NMR (400 MHz, CDCl 3 ) δ (ppm) 2H),21H),4H),5.49 (d,J = 3.5 Hz,1H),5.06 (d,J = 10.7 Hz,1H),4H),4.65 (d,J = 12.1 Hz,1H),4.58 (d,J = 12.0 Hz,1H),4.47 (d,J = 10.7 Hz,1H),4.39 (d,J = 12.0 Hz,1H),4.20 (ddd,J = 9.1,7.2,1.5 Hz,1H),5H), 3.53 (dd, J = 10.7, 1.5 Hz, 1H), 2.56 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ (ppm) 196.9, 196.9, 161.0, 160.4, 138.7, 138.4, 138.1, 138.0, 138.0, 137.9, 137.7, 131.9, 131.6, 130.6, 130.5, 128.6, 128.6, 128.5, 128.5, 128.5, 128.4, 128.3, 128.1, 128.1, 128.0, 128.0, 128.0, 128.0, 127.9, 127.8, 127.8, 127.8, 116.2, 100.8, 95.2, 84.6, 81.9, 81.9, 79.6, 77.6, 77.4, 76.0, 75.9, 75.3, 75.3, 75.2, 73.7, 73.6, 73.5, 71.2, 68.7, 68.0, 26.5;IR (in KBr) 3062, 3027, 2928, 1669, 1598, 1451, 1358, 1240, 1083 2H),18H),7.16 (dd,J = 7.4,2.2 Hz,2H),2H),5.53 (d,J = 3.6 Hz,1H),4.98 (d,…”