Lewis Base Catalyzed Enantioselective Allylic Hydroxylation of Morita–Baylis–Hillman Carbonates with Water
摘要:
A Lewis base catalyzed allylic hydroxylation of Morita-Baylis-Hillman (MBH) carbonates has been developed. Various chiral MBH alcohols can be synthesized in high yields (up to 99%) and excellent enantioselectivities (up to 94% ee). This is the first report using water as a nucleophile in asymmetric organocatalysis. The nucleophilic role of water has been verified using O-18-labeling experiments.
The first asymmetricorganocatalyticallylicalkylation of 1,2-dihydro-Reissert compounds and Morita–Baylis–Hillman (MBH) carbonates has been developed, which provided a novel protocol to construct enantioenriched functionalized 1,2-dihydroisoquinolines bearing vicinal quaternary and tertiary chiral centers at C-1 position (up to 94% ee, dr > 20 : 1).
Lewis base-catalyzed cyanation of Morita-Baylis-Hillman carbonates. Synthesis of allylamine derivatives
作者:Hai Ma、Feng Sui、Qing-He Zhao、Ning Zhang、Yi Sun、Jing Xian、Meng-Jiao Jiao、Yu-ling Liu、Zhi-Min Wang
DOI:10.1016/j.tetlet.2017.07.038
日期:2017.8
DABCO-catalyzed cyanation of MBH carbonates via 1,3-proton shift transfer is reported. The adducts of cyanation are converted in one step to allylic amines derivatives. The salient features of this reaction include readily available starting materials, mild conditions, broad substrate scope, high efficiency and valuable further applications. The process of the 1,3-proton shift transfer was conducted
Asymmetric Allylic Monofluoromethylation and Methylation of Morita-Baylis-Hillman Carbonates with FBSM and BSM by Cooperative Cinchona Alkaloid/FeCl2 Catalysis
yields with high ee values (see scheme, (DHQD)2AQN=hydroquinidine(anthraquinone‐1,4‐diyl) diether). The cooperativecatalysis of bis(cinchona alkaloid) and Lewis acid, particularly FeCl2, was effective for these transformations and gave the monofluoromethylation products with over 90 % ee and methylation products with up to 97 % ee.
The organocatalytic asymmetric allylic etherification reaction of Morita–Baylis–Hillmancarbonates and silanols was reported for the first time. With modified cinchonaalkaloid (DHQD)2PYR as the catalyst, a series of aromatic, heterocyclic, or aliphatic Morita–Baylis–Hillmancarbonates (25 examples) worked well with triphenylsilanol, affording the corresponding products in moderate to good yields (up
a cinchonine derived alkaloid, catalyzed asymmetric SN2′–SN2′ reaction between N-2,2,2-trifluoroethylisatin ketimines and MBH type carbonates was realized in a simple and efficient way. A series of chiral α-trifluoromethylamines were prepared with excellent yields and stereoselectivities. A subsequent and easy process of deprotection gave γ-trifluoromethyl-α-methylenelactam in a stereoselective manner
通过简单有效的方法,实现了由辛可宁衍生的生物碱β-异cupreidine催化的N -2,2,2-三氟乙基异丁酮酮与MBH型碳酸盐之间的不对称S N 2'–S N 2'反应。制备了一系列具有优异收率和立体选择性的手性α-三氟甲基胺。随后且容易的脱保护过程以立体选择性的方式得到了γ-三氟甲基-α-亚甲基内酰胺。