Asymmetric Michael Addition of
<i>N</i>
‐Boc‐Protected Oxindoles to Nitroalkenes Catalyzed by a Chiral Secondary Amine
作者:Chuan Wang、Xuena Yang、Dieter Enders
DOI:10.1002/chem.201200079
日期:2012.4.16
New mission for prolinol ethers: A secondary‐amine‐catalyzedMichaeladdition of N‐Boc‐protectedoxindoles to nitroalkenes through a Brønsted base activation mode has been developed, furnishing the products in excellent yields (88–98 %), diastereoselectivities (d.r.=98:2–>99:1) and high to excellent enantioselectivities (82–>99 % ee; see scheme).
Novel tartrate-derived guanidine-catalyzed highly enantio- and diastereoselective Michael addition of 3-substituted oxindoles to nitroolefins
作者:Liwei Zou、Xiaoze Bao、Yuanyuan Ma、Yuming Song、Jingping Qu、Baomin Wang
DOI:10.1039/c4cc01817f
日期:——
The Michael addition of 3-substituted oxindoles to nitroolefins was catalyzed by a novel tartrate-derived guanidine in high yield with excellent diastereo- and enantioselectivity. This method showed an extraordinarily broad substrate scope in terms of both reaction partners.
Michael Addition of N-Unprotected 2-Oxindoles to Nitrostyrene Catalyzed by Bifunctional Tertiary Amines: Crucial Role of Dispersion Interactions
作者:Christoph Reiter、Sònia López-Molina、Bernhard Schmid、Christian Neiss、Andreas Görling、Svetlana B. Tsogoeva
DOI:10.1002/cctc.201301052
日期:2014.3.5
Bifunctional thiourea‐ or sulfonamide‐derived tertiary aminescatalyze the enantioselective nitro‐Michaeladdition of N‐unprotected 3‐substituted 2‐oxindoles to nitrostyrene in up to 99 % yields, 94:6 er, and 87:13 dr. Overcoming the necessity to introduce and remove activating or protecting groups at the nitrogen moiety leads to a reduction of energy use, costs, and waste. Transition‐state geometries