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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(16):4654-4658
Catalytic asymmetric N‐alkylation of indoles and carbazoles represents a family of important but underdeveloped reactions. Herein, we describe a new organocatalytic strategy in which in situ generated aza‐para ‐quinone methides are employed as the alkylating reagent. With the proper choice of a chiral phosphoric acid and an N‐protective group, the intermolecular C−N bond formation with various indole and carbazole nucleophiles proceeded efficiently under mild conditions with excellent enantioselectivity and functional‐group compatibility. Control experiments and kinetic studies provided important insight into the reaction mechanism. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(42):13287-13291
The first enantioselective conjugate addition of silyl ketene imines to in situ generated indol‐2‐ones was performed in the presence of a chiral N ,N ′‐dioxide/NiII catalyst. This method provides efficient access to chiral β‐alkyl nitriles bearing congested vicinal all‐carbon quaternary stereocenters in up to 90 % yield with 23:1 d.r. and 98 % ee . The products enable facile transformations to chiral pyrroloindoline frameworks and spirocyclohexane oxindole derivatives. A possible transition state was also proposed to explain the origin of the asymmetric induction. 相似文献
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