- Enantioselective Stetter Reactions Catalyzed by Bis(amino)cyclopropenylidenes: Important Role for Water as an Additive
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The first highly enantioselective intermolecular Stetter reaction using simple enones is reported. A series of novel chiral BAC structures were designed and prepared. They were tested in the Stetter reaction with simple aldehydes and enones. The products were generated in excellent yields and enantioselectivities (up to 94% ee). Surprisingly, a substoichiometric amount of water was crucial to obtain high enantioselectivities. Chiral BACs were also shown to catalyze 1,6-conjugate addition reactions with paraquinone methides enantioselectively.
- Rezazadeh Khalkhali, Mehran,Wilde, Myron M. D.,Gravel, Michel
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p. 155 - 159
(2021/01/09)
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- A general, enantioselective synthesis of 2-substituted thiomorpholines and thiomorpholine 1,1-dioxides
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In the course of our drug discovery programs, we had need to access chiral, 2-substituted thiomorpholines and their oxidized congeners, thiomorpholine 1,1-dioxides. Here, we disclose a high-yielding, general protocol for the enantioselective synthesis of
- Reed, Carson W.,Lindsley, Craig W.
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- Addition of organometallic reagents to chiral N-methoxylactams: Enantioselective syntheses of pyrrolidines and piperidines
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Enantioselective iridium-catalyzed allylic substitutions were used to prepare N-allyl hydroxamic acid derivatives that were suitable for ring-closing metathesis, giving N-methoxylactams. Reactions of these derivatives with Grignard or organolithium compou
- Jaekel, Mascha,Qu, Jianping,Schnitzer, Tobias,Helmchen, Guenter
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p. 16746 - 16755
(2014/01/06)
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- Highly enantioselective synthesis of chiral allenes by sequential creation of stereogenic center and chirality transfer in a single pot operation
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Chiral allenes are readily accessed in a single pot operation in the reaction of terminal alkynes, aldehydes, chiral secondary amines, and zinc halides in good yields (up to 77% yield) and excellent enantioselectivities (up to 99% ee) in toluene at 120 °C. The reaction proceeds through initial formation of chiral propargylamine intermediates with creation of a new stereogenic center and subsequent chirality transfer via an intramolecular hydride shift to produce chiral allenes with high enantiomeric purities.
- Periasamy, Mariappan,Sanjeevakumar, Nalluri,Dalai, Manasi,Gurubrahamam, Ramani,Reddy, Polimera Obula
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supporting information; experimental part
p. 2932 - 2935
(2012/08/28)
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- Mukaiyama-Michael reactions with acrolein and methacrolein: A catalytic enantioselective synthesis of the C17-C28 fragment of pectenotoxins
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Enantioselective iminium-catalyzed reactions with acrolein and methacrolein are rare. A catalytic enantioselective Mukaiyama-Michael reaction that readily accepts acrolein or methacrolein as substrates, affording the products in good yields and 91-97% ee, is presented. As an application of the methodology, an enantioselective route to the key C17-C28 segment of the pectenotoxin using the Mukaiyama-Michael reaction as the key step is described.
- Kemppainen, Eeva K.,Sahoo, Gokarneswar,Valkonen, Arto,Pihko, Petri M.
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p. 1086 - 1089
(2012/03/27)
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- Efficient preparation of optically pure C2-symmetrical cyclic amines for chiral auxiliary
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Optically pure C2-symmetrical amines were efficiently synthesized from the corresponding diols obtained from the enantioselective borohydride reduction of the diketones catalyzed by the optically active β-ketoiminato cobalt(II) complex.
- Sato, Mitsuo,Gunji, Yasuhiko,Ikeno, Taketo,Yamada, Tohru
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p. 1434 - 1438
(2007/10/03)
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- A simple enantioselective preparation of (2S,5S)-2,5-diphenylpyrrolidine and related diaryl amines
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A short efficient catalytic asymmetric route to the preparation of C2-symmetric diaryl cyclic amines is described. Copyright (C) 2000 Elsevier Science Ltd.
- Aldous, David J.,Dutton, William M.,Steel, Patrick G.
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p. 2455 - 2462
(2007/10/03)
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