Stereoselective synthesis of polyols precursors by allyl sulphinyl anion addition to chiral alkoxy aldehydes

A comparison of homogeneous and heterogeneous Brønsted acid catalysts in the reactions of meso-erythritol with aldehyde/ketones

“…2 [33,34]. The products were identified by comparison with published 1 H and 13 C NMR data [35][36][37][38][39]. [33,34] A representative 1 H NMR spectrum of the bis-ketal (3b), ketal-ether (4b) product mixture from the Amberlite-15 catalyzed reaction of meso-erythritol (1), with acetone (2b) is shown in Fig.…”

“…90-91 °C (Lit. 89-90 °C [37]). The crystal of 3f (C 16 H 20 O 4 , M = 282.37) is orthorhombic, space group Pbca, at T = 100 K: a = 8.3505(18) Å, b = 7.5675(17) Å, c = 23.461(5) Å, α, β, γ = 90°, V = 1482.6(6) Å 3 , Z = 4, d calc = 1.265 g/cm 3 , F(000) = 616, μ = 0.089 mm −1 .…”

Total Syntheses of 3-epi-Litsenolide D2 and Lincomolide A

“…TIPSprotected 15 was prepared in a similar way to the synthesis of 7β. Colorless oil (121 mg, 0.293 mmol, 68%), [α] 25 D −16.2 (c 1.00, CHCl 3 ); IR (neat) 3456, 2931, 2862, 1466, 1250, 1134 cm −1 ; 1 H NMR (300 MHz, CDCl 3 ) δ 0.88 (t, J = 6.9 Hz, 3H), 1.04−1.11 (m, 21H), 1.17 (d, J = 5.8 Hz, 3H), 1.22−1.41 (m, 18H), 2.04 (dt, J = 6.9, 6.9 Hz, 2H), 2.69 (br d, J = 3.2 Hz, 1H), 3.74−3.84 (m, 2H), 5.42 (dd, J = 15.4, 6.7 Hz, 1H), 5.74 (dt, J = 15.4, 6.9 Hz, 1H); 13 C NMR (125 MHz, CDCl 3 ) δ 12.6 (CH), 12.6 (CH), 12.6 (CH), 14.1 (CH 3 ), 18.07 (CH 3 ), 18.07 (CH 3 ), 18.07 (CH 3 ), 18.14 (CH 3 ), 18.14 (CH 3 ), 18.14 (CH 3 ), 20 (4R,5R,E)-4,5-Bis((tert-butyldimethylsilyl)oxy)hex-2-en-1-ol (16). A mixture of 3 (119 mg, 0.685 mmol), TBSCl (372 mg, 2.47 mmol), imidazole (237 mg, 3.49 mmol), and DMAP (8.70 mg, 0.0712 mmol) in DMF (7.0 mL) was stirred at room temperature for 14.5 h and additionally stirred at 80 °C for 12.5 h. After the addition of H 2 O (10 mL) at 0 °C, the mixture was extracted with hexane/ EtOAc (2/1, 10 mL × 3), dried over MgSO 4 , and concentrated under reduced pressure.…”

“…[α] 25 D −17.6 (c 1.00, CHCl 3 ); IR (neat) 3348, 2954, 2931, 2854, 1257, 1095 cm −1 ; 1 H NMR (300 MHz, CDCl 3 ) δ 0.09 (s, 3H), 0.09 (s, 3H), 0.90 (s, 9H), 1.16 (d, J = 6.1 Hz, 3H), 1.39 (t, J = 5.8 Hz, 1H), 2.62 (d, J = 4.2 Hz, 1H), 3.67 (qd, J = 6.1, 6.1 Hz, 1H), 3.85 (dddd, J = 6.5, 6.1, 4.2, 1.1 Hz, 1H), 4.17 (dd, J = 5.8, 5.2 Hz, 2H), 5.69 (ddt, J = 15.5, 6.5, 1.5 Hz, 1H), 5.95 (dtd, J = 15.5, 5.2, 1.1 Hz, 1H); 13 C NMR (125 MHz, CDCl 3 ) δ −4.9 (CH 3 ), −4.3 (CH 3 ), 18.0 (C), 19.9 (CH 3 ), 25.8 (CH 3 ), 25.8 (CH 3 ), 25.8 (CH 3 ), 62.9 (CH 2 ), 71.8 (CH), 76.4 (CH), 130. 20 TBS-protected diol 17α was prepared from the enantiomer of 3 (ethyl (2E,4S,5S)-4,5-dihydroxy-2-hexenoate) in a similar way to the synthesis of 17β. The intermediate allyl alcohol 23 (ethyl (2E,4S,5S)-5-((tert-butyldimethylsilyl)oxy)-4-hydroxy-2-hexenoate), 19 Colorless oil (2.84 g, 9.85 mmol, 37%), [α] 25 D +4.6 (c 1.00, CHCl 3 ); IR (neat) 3479, 2954, 2931, 1720, 1257, 1095 cm −1 ; 1 H NMR (300 MHz, CDCl 3 ) δ 0.06 (s, 3H), 0.08 (s, 3H), 0.89 (s, 9H), 1.22 (d, J = 6.2 Hz, 3H), 1.29 (t, J = 7.1 Hz, 3H), 2.60 (d, J = 5.8 Hz, 1H), 3.77 (qd, J = 6.2, 5.0 Hz, 1H), 4.02 (dddd, J = 5.8, 5.0, 4.6, 1.7 Hz, 1H), 4.20 (q, J = 7.1 Hz, 2H), 6.12 (dd, J = 15.6, 1.7 Hz, 1H), 6.90 (dd, J = 15.6, 4.6 Hz, 1H); 13 C NMR (150 MHz, CDCl 3 ) δ −4.9 (CH 3 ), −4.4 (CH 3 ), 14.2 (CH 3 ), 18.0 (C), 20 (2S,3S,E)-Hexadec-4-ene-2,3-diol (19).…”

“…20 TBS-protected diol 17α was prepared from the enantiomer of 3 (ethyl (2E,4S,5S)-4,5-dihydroxy-2-hexenoate) in a similar way to the synthesis of 17β. The intermediate allyl alcohol 23 (ethyl (2E,4S,5S)-5-((tert-butyldimethylsilyl)oxy)-4-hydroxy-2-hexenoate), 19 Colorless oil (2.84 g, 9.85 mmol, 37%), [α] 25 D +4.6 (c 1.00, CHCl 3 ); IR (neat) 3479, 2954, 2931, 1720, 1257, 1095 cm −1 ; 1 H NMR (300 MHz, CDCl 3 ) δ 0.06 (s, 3H), 0.08 (s, 3H), 0.89 (s, 9H), 1.22 (d, J = 6.2 Hz, 3H), 1.29 (t, J = 7.1 Hz, 3H), 2.60 (d, J = 5.8 Hz, 1H), 3.77 (qd, J = 6.2, 5.0 Hz, 1H), 4.02 (dddd, J = 5.8, 5.0, 4.6, 1.7 Hz, 1H), 4.20 (q, J = 7.1 Hz, 2H), 6.12 (dd, J = 15.6, 1.7 Hz, 1H), 6.90 (dd, J = 15.6, 4.6 Hz, 1H); 13 C NMR (150 MHz, CDCl 3 ) δ −4.9 (CH 3 ), −4.4 (CH 3 ), 14.2 (CH 3 ), 18.0 (C), 20 (2S,3S,E)-Hexadec-4-ene-2,3-diol (19). A mixture of 18α (2.74 g, 7.72 mmol) and TBAF (8.5 mL, 8.50 mmol, 1.0 M in THF) in THF (39 mL) was stirred at room temperature for 15.5 h. After the addition of sat.…”