p-Toluenesulfonic acid → (2R,2'S,3'R,4'S,5'R,6'R)-3',4',5'-tris(benzyloxy)-6'-(benzyloxymethyl)-6-chloro-5-(4-ethylbenzyl)-2-methoxy-3',4',5',6'-tetrahydro-2H-spiro[benzofuran-3,2'-pyran]

Participants

Reaction Conditions

Reaction Steps

To a solution of 27 (35 mg, 44 μmol) in anhydrous MeOH (1 mL) and trimethylorthoformate (0.5 mL) was added 4-toluenesulfonic acid (15 mg). The mixture was heated in a closed vial at 70° C. overnight, cooled to ambient temperature, loaded onto a preparatory TLC plate, and developed using 15% EtOAc in petroleum ether to give 54 (25 mg, 70% yield). LC/MS m/z 834 (M+Na).

Provenance & Evidence