The enantioselective organocatalysed addition of β-keto benzothiazolesulfones to N-Boc-protected imines, leading to intermediates easily transformed into optically active allylic amines or β-keto amino compounds, is presented.
Three in one: Applying an organocatalytic tandem strategy to build a library of opticallyactive alkynyl, alkenyl, and ketone products, starting from cyclic enones and β‐keto sulfones, is shown to be rapid and efficient (see scheme; R=aryl, R′=H or alkyl).
三合一:从环烯酮和β-酮砜开始,应用有机催化串联策略建立光学活性炔基,烯基和酮产物的库是快速有效的(请参阅方案; R =芳基,R '= H或烷基)。
An Unexpected Michael-Aldol-Smiles Rearrangement Sequence for the Synthesis of Versatile Optically Active Bicyclic Structures by Using Asymmetric Organocatalysis
作者:Nicole Holub、Hao Jiang、Marcio W. Paixão、Caterina Tiberi、Karl A. Jørgensen
DOI:10.1002/chem.200903274
日期:2010.4.12
A facile and simple organocatalytic procedure to generate optically active 6‐alkyl‐ and 6‐aryl‐substituted bicyclo[2.2.2]oct‐5‐en‐2‐ones is presented. The reaction is catalysed by a 9‐amino‐9‐deoxyepiquinine trifluoroacetic acid salt, which activates α,β‐unsaturated cyclic ketones for the 1,4‐addition of β‐keto benzothiazoyl sulfones in a stereoselective fashion. Subsequent intramolecular aldol reaction
Transition-Metal-Free Formal Sonogashira Coupling and α-Carbonyl Arylation Reactions
作者:Birgit Prüger、Gretchen E. Hofmeister、Christian Borch Jacobsen、David G. Alberg、Martin Nielsen、Karl Anker Jørgensen
DOI:10.1002/chem.200902911
日期:2010.3.22
Sonogashira coupling and α‐carbonyl arylation reactions have been developed. These transformations are based on the nucleophilic aromatic substitution (SNAr) of β‐carbonyl sulfones to electron‐deficient aryl fluorides, producing a key intermediate that, depending on the reaction conditions, gives the aromatic alkynes or α‐aryl carbonyl compounds. The development of these reactions is presented and, based
An asymmetric allylic alkylation of Morita–Baylis–Hillmancarbonates and β-keto sulfones was investigated by the catalysis of modified cinchonaalkaloids, whose products underwent a Smiles rearrangement–sulfinate addition cascade to furnish highly functionalized five-membered cyclic sulfones in moderate to excellent enantioselectivity and good diastereoselectivity after treatment with DBU.