摘要：

5- endo -trig cyclisation of the ( Z )-hydroxyalkenoate 17 using iodine as the electrophile gave a good yield of the -hydroxytetrahydrofuran 18 , probably via the corresponding iodohydrin. A variety of one-carbon degradation methods were then used to generate precursors to (-)-muscarine ( 25d ). An alternative strategy featured control of a 5- endo -trig iodocyclisation by an allylic hydroxyl group, which can be used for the highly stereocontrolled synthesis of hydroxy-iodotetrahydrofurans 28 . Application of this strategy to the ( Z )-alkenediol derivative 38 led to an excellent yield of the tetrahydrofuran 39 when iodine monobromide was used as the electrophile. Two simple and efficient transformations then gave the (+)-muscarine precursor 40b . (? Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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