Total Synthesis of Indolizidine Alkaloid (−)-209D: Overriding Substrate Bias in the Asymmetric Rhodium-Catalyzed [2+2+2] Cycloaddition
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چکیده
منابع مشابه
Total synthesis of the indolizidine alkaloid tashiromine
BACKGROUND Tashiromine 1 is a naturally occurring indolizidine alkaloid. It has been the subject of thirteen successful total syntheses to date. Our own approach centres on the stereoselective construction of the indolizidine core by capture of an electrophilic acyliminium species by a pendant allylsilane. The key cyclisation precursor is constructed using olefin cross-metathesis chemistry, whi...
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The rhodium(II)-catalyzed formation of 1,3-dipoles has played a major role in facilitating the use of the dipolar cycloaddition reaction in modern organic synthesis. This is apparent from the increasing number of applications of this chemistry for the construction of heterocyclic and natural product ring systems. This chapter initially focuses on those aspects of rhodium(II) catalysis that cont...
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A rhodium-catalyzed regioand enantioselective synthesis of silicon-stereogenic silicon-bridged arylpyridinones has been developed through [2 + 2 + 2] cycloaddition of silicon-containing prochiral triynes with isocyanates. High yields and enantioselectivities have been achieved by employing an axially chiral monophosphine ligand, and this process could be applied to catalytic asymmetric synthesi...
متن کاملSynthesis of the Benzo-fused Indolizidine Alkaloid Mimics
A general synthesis of various benzo-fused indolizidine alkaloid mimics has been developed. The indolizidine derivatives 8 were prepared via heteroaryl Grignard addition to N-acylpyridinium salts followed by an intramolecular Heck cyclization. Further substitution reactions were developed to demonstrate that heterocycles 8 are good scaffolds for chemical library preparation.
متن کاملRhodium-catalyzed asymmetric conjugate alkynylation of nitroalkenes.
Asymmetric addition of (triisopropylsilyl)acetylene to nitroalkenes took place in the presence of a rhodium/chiral bisphosphine catalyst to give beta-alkynylated nitroalkanes in high yields with high enantioselectivity.
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ژورنال
عنوان ژورنال: Angewandte Chemie International Edition
سال: 2009
ISSN: 1433-7851
DOI: 10.1002/anie.200805455