Total synthesis of avrainvillamide (CJ-17,665) and stephacidin B.

General Procedures. All reactions were carried out under an inert nitrogen atmosphere unless otherwise stated. All reagents were purchased at the highest commercial quality and used as received unless otherwise stated. Dry methanol (MeOH), dichloromethane (CH2Cl2), benzene, toluene (PhMe), triethylamine (Et3N), and tetrahydrofuran (THF) were obtained by passing these previously degassed solvents through activated alumina columns. Glacial acetic acid (AcOH) was purchased at ACS Plus commercial quality from Fisher Scientific and used as received. Acetone and 1,4-dioxane were distilled and stored in amber glass bottles. N, N-diisopropylethylamine was distilled over calcium hydride and stored over potassium hydroxide pellets in an amber glass bottle. Pd2dba3•CHCl3 was prepared according to a published procedure. Lithium diisopropylamide (LDA; 0.5 M in THF) was generated as needed from distilled diisopropylamine and n-butyllithium (2.5 M in hexanes) by standard methods. Fe(acac)3 was recrystallized from EtOH and dried under high vacuum for 12 hours prior to use. The Burgess reagent was prepared according to the published procedure. Sodium cyanoborohydride [NaBH3CN], 95%, was puchased from Alfa Aesar and used without further purification. Sodium tungstate dihydrate (Na2WO4•2H2O), ACS reagent grade, was purchased from Acros Organics and used without further purification. 35% aqueous hydrogen peroxide (H2O2) was purchased from Acros Organics, used as received, and stored at 0 °C. Selenium dioxide (SeO2), 99%, was purchased from Aldrich and used as received. Yields refer to chromatographically and spectroscopically (H NMR) homogenous material, unless otherwise stated. Reactions were monitored by thin layer chromatography carried out on 0.25 mm E. Merck silica gel plates (60F-254) using UV light as the visualizing agent and an acidic anisaldehyde, acidic phsphomolybdic acid, or basic aqueous potassium permanganate (KMnO4) and heat as developing agents. E. Merck silica gel (60, particle size 0.043–0.063 mm) was used for flash column chromatography. Preparative thin layer chromatography (PTLC) separations were carried out on 0.25, 0.5, or 1.0 mm E. Merck silica gel plates (60F-254). Optical rotation measurements were recorded on a Perkin Elmer Model 341 polarimeter using a 10 cm (1 mL capacity) cell. NMR spectra were recorded on a Bruker DRX-500 instrument and calibrated using residual undeuterated solvent as internal reference. The following