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J Nakano K Masuda Y Yamashita S Kobayashi 《Angewandte Chemie (International ed. in English)》2012,51(38):9525-9529
First walk, then run! Highly efficient organosuperbase-catalyzed Mannich-type reactions of sulfonylimidates with readily prepared Boc-protected imines have been developed. The desired products were obtained in high yield and with high anti selectivity. Mechanistic studies show an induction period for the catalyzed reaction, and that the organosuperbase works as an initiator. 相似文献
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Prof. Henryk Krawczyk Dr. Marek Dzięgielewski Dr. Dariusz Deredas Dr. Anna Albrecht Dr. Łukasz Albrecht 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10268-10277
Chiral Brønsted base catalysis is a fascinating and highly explored field of research. For many years catalysts based on chincona alkaloid chiral scaffolds have constituted privileged systems widely employed in numerous base‐promoted organic transformations. Recently, a novel group of chiral base catalysts has been successfully introduced. The application of organosuperbases, namely cyclopropenimines, guanidines, and iminophosphoranes, as chiral catalysts is receiving increasing attention. The aim of this Concept article is to summarize recent progress in the field of chiral iminophosphorane superbase organocatalysis. Catalysts design, different approaches to their synthesis, and applications in asymmetric synthesis are outlined and discussed in detail. 相似文献
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Very Strong Organosuperbases Formed by Combining Imidazole and Guanidine Bases: Synthesis,Structure, and Basicity
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Dr. Katarina Vazdar Dr. Roman Kunetskiy M. Sc. Jaan Saame M. Sc. Karl Kaupmees Prof. Dr. Ivo Leito Dr. Ullrich Jahn 《Angewandte Chemie (International ed. in English)》2014,53(5):1435-1438
New structural motives for organosuperbases, that are easy to prepare and highly basic are urgently required in many areas of chemistry. The synthesis of N,N′‐bis(imidazolyl)guanidine bases (BIG bases) is reported. Their pKα values are determined as 26.1–29.3 in THF. They are thus probably the strongest known phosphorous‐free organic bases both in solution and in the gas phase. Calculations help to determine the structural and electronic factors giving rise to the high basicity. 相似文献
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Enantioselective Addition of a 2‐Alkoxycarbonyl‐1,3‐dithiane to Imines Catalyzed by a Bis(guanidino)iminophosphorane Organosuperbase
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Dr. Azusa Kondoh Masafumi Oishi Tadahiro Takeda Prof. Dr. Masahiro Terada 《Angewandte Chemie (International ed. in English)》2015,54(52):15836-15839
A chiral bis(guanidino)iminophosphorane catalyzes enantioselective addition reactions of a 1,3‐dithiane derivative as a pronucleophile. The chiral uncharged organosuperbase facilitates the addition of benzyloxycarbonyl‐1,3‐dithiane to aromatic N‐Boc‐protected imines to provide optically active α‐amino‐1,3‐dithiane derivatives, which are valuable versatile building blocks in organic synthesis. 相似文献
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Cover Picture: Enantioselective Addition of a 2‐Alkoxycarbonyl‐1,3‐dithiane to Imines Catalyzed by a Bis(guanidino)iminophosphorane Organosuperbase (Angew. Chem. Int. Ed. 52/2015)
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