10-But-3-enyl-2,2-dimethyl-6-vinyloctahydronaphtho-[1,8a-d][1,3]dioxole (46):

A catalytic amount of TPAP (1 crystal) and NMO (14 mg, 0.12 mmol) was added to a solution of diol 44 in acetonitrile (1 mL) over 4 Å molecular sieves (50 mg). The reaction was stirred for 20 min. The mixture was then filtered through a silica gel pad (5% methanol/95% ethyl acetate). The solvent was evaporated, and the crude dialdehyde 45 was used immediately to avoid decomposition (see below).

Methyl-triphenylphosphonium iodide (0.057 g, 0.14 mmol)was dissolved in tetrahydrofuran (1 mL) and cooled to 0�C. KHMDS (10.43 M in toluene, 0.325 mL, 0.14 mmol) was added, and the solution turned yellow. This will be referred to as the ylide solution , due to the phosphorus ylide complex (this is explained in detail in the .

Dialdehyde 45 (0.010 g, 0.03 mmol) in tetrahydrofuran (1 mL) was mixed into the ylide solution. The reaction was stirred at 0 �C for 30 minutes. The reaction was quenched by adding saturated NH 4 Cl (aq) . The aqueous layer was extracted 3 times with diethyl ether (3 x 10 mL). The organic layer was dried over anhydrous MgSO 4 , filtered, and the solvent was evaporated. The crude product was purified by flash column chromatography using silica (10% Ethyl Acetate/hexanes) to yield 7 mg of 46 (72% yield) eluting as a colorless oil. (H 1 NMR data provided above with assignments from 500 MHz machine using CDCl 3 as the solvent)

Notes:

• TPAP is the RuO 4 shown in the first step of the reaction mechanism
• NMO is nitrogen monoxide (NO) as shown in the reaction mechanism
• Acetonitrile is (CH 3 )CN as shown in the reaction mechanism
• 4 Å molecular sieve are crystalline metal aluminosilicates having a three-dimensional interconnecting network of silica and alumina tetrahedra. Natural water of hydration is removed from this network by heating to produce uniform cavities which selectively adsorb molecules of a specific size (4 Å here). Long known for their drying capacity (even to 90°C), molecular sieves have recently demonstrated utility in synthetic organic procedures, frequently allowing isolation of desired products from condensation reactions that are governed by generally unfavorable equilibria. They have been shown to remove water, alcohols (including methanol and ethanol), and HCl from such systems as ketimine and enamine syntheses, ester condensations, and the conversion of unsaturated aldehydes to polyenals.
• A silica gel pad is a crude filtering device that can easily separate a mixture with solid and certain types of liquid impurities
• Solvent evaporation is carried out through roto-vaping technique which uses vacuum and heat to evaporate the organic solvents
• Methyl-triphenylphosphonium iodide is the ylide reagent for the Wittig olefination reaction with iodide to stabilize the charge shown in the reaction mechanism
• KHMDS is a silicon-containing reagent that carries a negative charge with a positively-charged potassium atom. This reagent stabilizes the iodine so the ylide (above) can work correctly. (this does not affect the reaction mechanism
• Tetrahydrofuran is a solvent
• NH 4 Cl will interact with the excess ylide to stop the reaction
• MgSO 4 is a drying agent for removing water
• Flash column chromatography is a method for eluting a product amongst impurities in solution using specified solvents that give good (and measurable) separation on TLC