Regioselectivities in alkyne activation: synthesis of 2-(bicyclo[3.1.0]hexan-1-yl)furan derivatives by Au-catalyzed cyclization and cyclopropanation.
نویسندگان
چکیده
2-Alkynyl-1-cycloalkenecarbaldehydes, in the presence of gold catalysts, undergo aurative cyclization via the 5-exo-dig mode to form Au-carbene intermediates which react with a double bond to form the corresponding cyclopropanes.
منابع مشابه
Synthesis of 3-aza-bicyclo[3.1.0]hexan-2-one derivatives via gold-catalyzed oxidative cyclopropanation of N-allylynamides.
N-allylynamides with various functional groups and different substitution patterns can be converted into 3-aza-bicyclo[3.1.0]hexan-2-one derivatives in moderate to high yield using IMesAuCl/AgBF4 as the catalyst and pyridine N-oxide as the oxidant. A noncarbene mediated approach is proposed as the mechanism.
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Phosphine catalyzed enantioselective [3+2] cyclizations on 4-substituted 2,6-diarylidenecyclohexanones and 2,4-diarylidene-bicyclo[3.1.0]hexan-3-ones take place with high diastereo- and enantioselectivity levels. The process affords spirocyclic compounds with excellent stereochemical control of up to five stereogenic centres.
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The Lewis acid catalyzed cyclization of hexatrienes and pentadienals to bicyclo[3.1.0]hexenes and cyclopentenones, respectively, was investigated. The application of the former reaction to the total synthesis of photodeoxytridachione, a molluscan polypropionate, is described. q 2003 Elsevier Ltd. All rights reserved.
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We here describe a new palladium-catalyzed oxidative 6-exo-trig cyclization of 1,6-enynes at room temperature using tBuONO as an oxidant for the synthesis of 3-bicyclo[4.1.0]heptan-5-ones. This cascade strategy involves the hydration, cyclization and cyclopropanation sequence, and represents a new transition-metal-catalyzed oxidative cyclization of 1,6-enynes in a 6-exo-trig fashion.
متن کاملPlatinum- and gold-catalyzed cycloisomerization reactions of hydroxylated enynes.
Exposure of enynes containing a hydroxyl group at one of the propargylic positions to catalytic amounts of either PtCl2 or (PPh3)AuCl/AgSbF6 results in a selective rearrangement with formation of bicyclo[3.1.0]hexan-3-one derivatives. The same products are obtained by a "one-pot" process on treatment of an alkynal with allylchlorodimethylsilane (4) and PtCl2 via a reaction cascade involving an ...
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ورودعنوان ژورنال:
- Chemical communications
دوره 44 شماره
صفحات -
تاریخ انتشار 2008