金(I)催化8-芳香環-2-烯-7-炔-1-辛醇進行分子內克來森類型重排反應合成非鏡像選擇性1,2-雙取代環戊烷衍生物

The cyclopentanes are frequently found in a variety of natural products. Therefore, the development of practical and facile synthetic routes for the synthesis of stereoselective five-membered ring derivatives is important. In the thesis, we report that gold and silver cocatalyzed intramolecular Claisen-type rearrangement of (E)-8-phenyloct-2-en-7-yn-1-ol (enynol) produces 1-phenylcarbonyl-2-vinylcyclopentanes in diastereoselective fashion. Reaction of hex-5-yn-1-ol with aryl iodine catalyzed by palladium(0)under Sonogashira reaction conditions produces 6-arylhex-5-yn-1-ol. Oxidation of 6-arylhex-5-yn-1-ol with IBX (2- iodoxybenzoic acid) affords 6-arylhex-5-yn-1-al. The resulting aldehyde was treated with (2-ethoxy-2-oxoethyl)triphenylphosphonium bromide to afford (E)-ethyl 8-phenyloct-2-en-7-ynoate. Reduction of the (E)-ethyl-8-phenyloct-2-en-7-ynoate using DIBAL(Diisobutylaluminium hydride) generated (E)-8-phenyloct-2-en-7-yn-1-ol. Treatment of the enynol with 10 mol % Ph3PAuCl / AgOTf in toluene at reflux produced 1-phenylcarbonyl-2-vinylcyclopentanes. The formation of the cyclopentane derivative is believed to undergo intramolecular Claisen-type rearrangement. The X-ray diffraction analysis reveals that the relative stereochemistry of the vinyl and the keto is trans.