A radical cyclization of beta-alkoxyvinyl sulfoxides-Pummerer rearrangement-allylation protocol was successfully applied to the synthesis of the threo/cis/threo/cis/erythro bis-oxolane moiety in rolliniastatin 1 (1), rollimembrin (2), and membranacin (3).

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All reactions were performed under argon atmosphere. 1 H and 13 C NMR spectra were measured on 300 MHz, 400 MHz and 500 MHz spectrometers. Chemical shift values were recorded in parts per million using the residual undeuterated solvents as internal references and coupling constants in hertz. Infrared spectra (IR) were recorded on a FT-IR spectrophotometer and frequencies are given in reciprocal centimeters. Mass spectra (MS and HRMS) were recorded using chemical ionization (CI), electron impact (EI), or fast atom bombardment (FAB) method. Optical rotation data were obtained on a digital polarimeter at 589 nm (sodium D line).The progress of reactions was checked on TLC plates, and the spots were visualized under 254 nm UV light and/or charring after dipping the TLC plate into p-anisaldehyde solution (ethanol 67.5 mL, p-anisaldehyde 1.85 mL, acetic acid 0.75 mL, and sulfuric acid 2.5 mL).All solvents used in reactions were dried under nitrogen atmosphere. THF and toluene were distilled from Na-benzophenone. Acetonitrile and triethylamine were distilled from CaH 2 . CH 2 Cl 2 was distilled from P 2 O 5 . Dry solvents purchased from Aldrich Chem. Co. (THF, CH 2 Cl 2 , toluene and pyridine) were also used.