General Procedure B. To a solution of alkene (1.0 eq.) in dioxane (18 mL/mmol) and water (4.6 mL/mmol) was added NaIO4 (4.0 eq.), 2,6-lutidine (2.0 eq.) and 4% OsO4 in water (0.01 eq.). The reaction was left to stir at r.t. for 16 h. The resulting white suspension was quenched with saturated Na2SO3 solution, extracted with DCM (4 × 10 mL), dried with MgSO4, and concentrated in vacuo. The residue is then purified by flash column chromatography using a linear gradient of 0% to 10% MeOH in DCM to yield aldehydes as colourless oils.