共查询到20条相似文献,搜索用时 15 毫秒
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(8):2054-2057
The enantioselective 1,2‐reduction of α,β‐unsaturated ketones was achieved using a NiH catalyst in the presence of pinacolborane. This mild process represents a general method to access a wide variety of structurally diverse α‐chiral allylic alcohols in excellent yields and enantioselectivity, as well as very high levels of ambidoselectivity for 1,2‐ over 1,4‐reduction. Furthermore, for reactions on a 10 mmol scale, catalyst loadings as low as 0.5 mol % could be employed to deliver product without any detrimental effect on the yield, enantio‐, or ambidoselectivity. 相似文献
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Prof. Dr. Benjamin List Dr. Ilija Čorić Dr. Oleksandr O. Grygorenko Philip S. J. Kaib Prof. Dr. Igor Komarov Dr. Anna Lee Markus Leutzsch Dr. Subhas Chandra Pan Andrey V. Tymtsunik Manuel van Gemmeren 《Angewandte Chemie (International ed. in English)》2014,53(1):282-285
The first aminocatalyzed α‐alkylation of α‐branched aldehydes with benzyl bromides as alkylating agents has been developed. Using a sterically demanding proline derived catalyst, racemic α‐branched aldehydes are reacted with alkylating agents in a DYKAT process to give the corresponding α‐alkylated aldehydes with quaternary stereogenic centers in good yields and high enantioselectivities. 相似文献
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Nis Halland Tore Hansen Karl Anker Jrgensen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2003,115(40):5105-5107
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Guangying Tan Yimin Wu Yang Shi Jingsong You 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(22):7518-7522
The hydroformylation of alkynes is a fundamental and important reaction in both academic research and industry. Conventional methods focus on the conversion of alkynes, CO, and H2 into α,β‐unsaturated aldehydes, but they often suffer from problems associated with operation, regioselectivity, and chemoselectivity. Herein, we disclose an operationally simple, mild, and syngas‐free rhodium‐catalyzed reaction for the hydroformylation of alkynes via formyl and hydride transfer from an alkyl aldehyde. This synthetic method uses inexpensive and easy‐to‐handle n‐butyraldehyde to overcome the challenge posed by the use of syngas in traditional approaches and employs a commercially available catalyst and ligand to transform a broad range of internal alkynes, especially alkynyl‐containing complex molecules, into versatile stereodefined α,β‐unsaturated aldehydes with excellent chemo‐, regio‐, and stereoselectivity. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7568-7572
An additive‐free nickel‐catalyzed α‐allylation of aldehydes with allyl alcohol is reported. The reaction is promoted by 1 mol % of in situ formed nickel complex in methanol, and water is the sole by‐product of the reaction. The experimental conditions allow the conversion of various α‐branched aldehydes and α,β‐unsaturated aldehydes as nucleophiles. The same catalyst and reaction conditions enabled a tandem aldol condensation of aldehyde/α‐allylation reaction. 相似文献