Applications of the Chiral Auxiliaries DIOZ and TRIOZ for Conjugate Additions and Comparison with Other Auxiliaries
نویسندگان
چکیده
منابع مشابه
Highly selective acetate aldol additions using mesityl-substituted chiral auxiliaries.
[reaction: see text] Highly diastereoselective acetate aldol additions using chlorotitanium enolates of mesityl-substituted N-acetyloxazolidinethione and N-acetylthiazolidinethione auxiliaries are reported. These additions proceed in high yields and diastereoselectivities (93:7 to 98:2) for aliphatic, aromatic, and ,-unsaturated aldehydes. Double diastereoselective acetate aldol additions are a...
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Background The use of chiral auxiliaries in the synthesis of enantiomerically pure compounds has found wide application for a variety of reactions over the last three decades. Despite the extensive developments in this area by many academic and industrial research groups, new auxiliary controlled reactions continue to evolve frequently [1]. First objectives in this area have been to develop chi...
متن کاملHelicene-Based Chiral Auxiliaries and Chirogenesis
Helicenes are unique helical chromophores possessing advanced and well-controlled spectral and chemical properties owing to their diverse functionalization and defined structures. Specific modification of these molecules by introducing aromatic rings of differing nature and different functional groups results in special chiroptical properties, making them effective chiral auxiliaries and supram...
متن کاملTitanium enolates of thiazolidinethione chiral auxiliaries: versatile tools for asymmetric aldol additions.
[formula: see text] Asymmetric aldol additions using chlorotitanium enolates of thiazolidinethione propionates proceed with high diastereoselectivity for the "Evans" or "non-Evans" syn product depending on the nature and amount of the base used. With (-)-sparteine as the base, selectivities of 97:3 to > 99:1 were obtained for the Evans syn products with 2 equivalents of base and for the non-Eva...
متن کاملDirect Enantioselective Conjugate Addition of Carboxylic Acids with Chiral Lithium Amides as Traceless Auxiliaries
Michael addition is a premier synthetic method for carbon-carbon and carbon-heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueou...
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ژورنال
عنوان ژورنال: Helvetica Chimica Acta
سال: 2010
ISSN: 0018-019X,1522-2675
DOI: 10.1002/hlca.200900385