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Two Contrasting Asymmetric Approaches to Muscarine Based on 5‐ endo ‐trig Cyclisations
Author(s) -
Knight David W.,
Shaw Duncan E.,
Staples Emily R.
Publication year - 2004
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300647
Subject(s) - chemistry , muscarine , electrophile , tetrahydrofuran , allylic rearrangement , yield (engineering) , derivative (finance) , organic chemistry , catalysis , biochemistry , materials science , receptor , muscarinic acetylcholine receptor , solvent , economics , financial economics , metallurgy
Abstract 5‐ endo ‐trig cyclisation of the ( Z )‐hydroxyalkenoate 17 using iodine as the electrophile gave a good yield of the β‐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)