Transannular anti-Michael addition: formation of 4H-pyrazolo[5,1-c]thiazines
نویسندگان
چکیده
منابع مشابه
C-H Oxidation/Michael Addition/Cyclization Cascade for Enantioselective Synthesis of Functionalized 2-Amino-4H-chromenes.
A streamlined method for the enantioselective synthesis of 2-amino-4H-chromenes from readily available 2-alkyl-substituted phenols and active methylene compounds bearing a cyano group with up to 97% ee is presented. This reaction is a cascade procedure including manganese dioxide mediated C-H oxidation for the generation of o-quinone methides and bifunctional squaramide-catalyzed Michael additi...
متن کاملEnantioselective Michael Addition of Water
The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method...
متن کامل"Anti-Michael addition" of Grignard reagents to sulfonylacetylenes: synthesis of alkynes.
In this work, the addition of Grignard reagents to arylsulfonylacetylenes, which undergoes an "anti-Michael addition", resulting in their alkynylation under very mild conditions is described. The simplicity of the experimental procedure and the functional group tolerance are the main features of this methodology. This is an important advantage over the use of organolithium at -78 °C that we pre...
متن کاملPhosphine-catalyzed regioselective Michael addition to allenoates.
The first phosphine catalysed Michael addition of arylcyanoacetates to allenoates has been developed, and the β-selective products with a quaternary center were obtained in excellent yields. This unusual regioselectivity may open new opportunities to access interesting molecular structures.
متن کاملA macrocyclic approach to tetracycline natural products. Investigation of transannular alkylations and Michael additions.
A new approach to the tetracycline core structure is presented. The pivotal intermediate is identified as macrocycle III. The two interior bonds (C4a-C12a and C5a-C11a) are to be constructed through sequential transannular Michael additions (III-II) and compression-promoted transannular isoxazole alkylations from intermediate II.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Tetrahedron Letters
سال: 2006
ISSN: 0040-4039
DOI: 10.1016/j.tetlet.2006.09.015