The First Enantioselective Organocatalytic Mukaiyama−Michael Reaction: A Direct Method for the Synthesis of Enantioenriched γ-Butenolide Architecture
作者:Sean P. Brown、Nicole C. Goodwin、David W. C. MacMillan
DOI:10.1021/ja029095q
日期:2003.2.1
an important chiralsynthon found among many natural isolates. The (2S,5S)-5-benzyl-2-tert-butyl-imidazolidinone amine catalyst has been found to mediate the conjugate addition of a wide variety of substituted and unsubstituted silyloxy furans to unsaturated aldehydes. A diverse range of aldehyde substrates can be accommodated in this new organocatalytic transformation. Application of this new asymmetric
Mukaiyama-Michael Reactions with<i>trans</i>-2,5-Diarylpyrrolidine Catalysts: Enantioselectivity Arises from Attractive Noncovalent Interactions, Not from Steric Hindrance
作者:Eeva K. Kemppainen、Gokarneswar Sahoo、Antti Piisola、Andrea Hamza、Bianka Kótai、Imre Pápai、Petri M. Pihko
DOI:10.1002/chem.201304240
日期:2014.5.12
the predicted and observed stereoselectivities. The analysis of intermolecular forces reveals that the enantioselectivity is mostly due to stabilizing noncovalentinteractions between the reacting partners, not due to sterichindrance. The role of attractivenoncovalentinteractions in enantioselective catalysis may be underappreciated.
作者:Yong Huang、Abbas M. Walji、Catharine H. Larsen、David W. C. MacMillan
DOI:10.1021/ja055545d
日期:2005.11.1
cascade catalysis protocols allow the invention of enantioselective transformations that were previously unknown, including the asymmetriccatalyticaddition of the elements of HF across a trisubstituted olefin. Importantly, these domino catalysis protocols can be mediated by a single imidazolidinone catalyst or using cycle-specific amine catalysts. In the latter case, cascade catalysis pathways can
基于生物合成的生化蓝图的有机催化新策略为级联催化提供了一种新的实验室方法。基于咪唑烷酮的催化循环,涉及亚胺和烯胺活化,已成功结合,使多种亲核试剂(呋喃、噻吩、吲哚、丁烯内酯、氢化物源、叔氨基内酯等价物)和亲电子试剂(氟化和氯化试剂)经历与各种 α,β-不饱和醛连续添加。这些新的级联催化方案允许发明以前未知的对映选择性转化,包括 HF 元素在三取代烯烃上的不对称催化加成。重要的,这些多米诺催化方案可以通过单一的咪唑啉酮催化剂或使用循环特定的胺催化剂来调节。在后一种情况下,通过对胺催化剂的对映体系列的明智选择,可以容易地调节级联催化途径以提供所需的非对映选择性和对映选择性结果。将多个不对称有机催化事件组合成一个序列的一个主要好处是在第二个诱导循环中对映体富集的内在要求,正如本研究中获得的对映体选择性所证明的(>/=99% ee 在所有情况下)。通过对胺催化剂的对映体系列的明智选择,可以很容易地
N-Substituted tertiary and O-substituted quaternary carbon stereogenic centers by site-, diastereo- and enantioselective vinylogous Mannich reactions
作者:Daniel L. Silverio、Peng Fu、Emma L. Carswell、Marc L. Snapper、Amir H. Hoveyda
DOI:10.1016/j.tetlet.2015.04.006
日期:2015.6
accessible small-molecule phosphine, derived from commercially available starting materials such as an enantiomerically pure amino acid, serves as the precursor to a Ag-based chiral complex that can be prepared and used in situ to promote a variety of enantioselective vinylogous Mannich (EVM) reactions that involve siloxypyrroles as reaction partners. Transformations with unsubstituted nucleophilic components
synthetic strategy that affords a range of diverse cyclic benzo-sulfonamide scaffolds is presented. Whereas different annulation reactions on common ketimine substrates build the branching phase of the scaffoldsynthesis, a common hydrogenative ring-expansion method, facilitated by an increase of the ring-strain during the branching phase, led to sulfonamides bearing medium-sized rings in a folding pathway