6-Phenylethyl-5,6-dihydro-2-pyrones From Aniba gigantifolia

Spiro[3.5]nonenyl Meroterpenoid Lactones, Cryptolaevilactones G–L, an Ionone Derivative, and Total Synthesis of Cryptolaevilactone M from Cryptocarya laevigata

“…The title aldehyde (9, 399 mg, 2.12 mmol) was obtained as a colorless oil without further purification. 1 H NMR (400 MHz, CDCl 3 ) δ 0.07 (s, 6H), 0.88 (s, 9H), 2.60 (dt, J = 2.0 Hz, 2H), 3.99 (t, J = 6.0 Hz, 2H), 9.81 (t, J = 2.4 Hz, 1H).…”

“…The solution was extracted with CH 2 Cl 2 , washed with brine, dried over Na 2 SO 4 , and concentrated under reduced pressure. The residue was purified with silica gel column chromatography (nhexane−EtOAc, 10:1) to afford 10 (431 mg, 70%, > 99% ee by 1 H NMR spectroscopy of its MTPA ester; see Supporting Information) as a colorless oil: 1 (3R)-1-[(tert-Butyldimethylsilyl)oxyl]-3-[(tert-butyldiphenyl)oxyl]hex-5-ene (11). To a stirred solution of alcohol 10 (386 mg, 1.68 mmol) in anhydrous CH 2 Cl 2 (6.0 mL) was added imidazole (348 mg, 5.12 mmol) followed by TBDPSCl (0.86 mL, 3.…”

“…The combined organic phases were washed with brine, dried over Na 2 SO 4 , and concentrated in vacuo. The residue was purified by silica gel column chromatography (n-hexane− Et 2 O, 10:1) to give ester 14 (246 mg, 74% in 2 steps) as a colorless oil: 1 ( 4 R , 6 S ) -8 -[ ( t e r t -B u t y l d i m e t h y l s i l y l ) o x y ] -6 -[ ( t e r tbutyldiphenylsilyl)oxy]oct-1-en-4-yl Acrylate (15). To a solution of 14 (99 mg, 0.18 mmol) in degassed CH 2 Cl 2 (25 mL) at rt was added the second-generation Grubbs catalyst (13 mg, 0.017 mmol).…”

“…The residue was purified by column chromatography (n-hexane−EtOAc, 4:1) to give 17 (28 mg, 42%) as a colorless oil. Diastereomeric mixture: 1 (R)-6-{(R,E)-2-[(tert-Butyldiphenylsilyl)oxy]-4-oxo-8-phenyloct-7en-1-yl}-5,6-dihydro-2H-pyran-2-one (18). A solution of alcohol 17 (16 mg, 0.028 mmol) in anhydrous CH 2 Cl 2 (4.0 mL) was added to IBX (30 mg, 0.107 mmol) in anhydrous DMSO (2.0 mL).…”

“…14 13 C NMR data of 3 showed similar, but slightly shifted, signal patterns compared to those of 1, consistent with 3 being a diastereomer (Tables 1 and 2). The relative configuration of 3 was determined from the NOESY correlations between H-11/H-7′α, H-12/H-7′β, H-12/H-6′β, H-7′α/H-2′, H-5′α/H-6′α, and H-4′α/H-5′α (Figure 2), as well as the following 1 calculated 33 ECD data supported the (6S, 11R, 12S, 1′S, 4′S) absolute configuration (Figure 3). The 1 H NMR data of 4 and 3 (Table 1) were quite similar; however, the signals related to the spiro moiety, H-2′−H-4′ as well as H-5′ α,β and H-6′ α,β , were shifted, suggesting a different configuration at C-1′.…”