30457-88-6Relevant articles and documents
Rh(III)-Catalyzed Csp2?Csp3 Bond Cleavage/Carbonylethylation of α-Indolyl Alcohols
Liu, Zhipeng,Hu, Xinwei,Yang, Can,Xie, Haisheng,Jiang, Huanfeng,Zeng, Wei
, p. 1672 - 1684 (2021)
A Rh(III)-catalyzed Csp2?Csp3 bond cleavage/carbonylethylation of α-indolyl alcohols with allylic alcohols has been reported. This transformation involved a cascade C?C bond cleavage/C?C bond formation, and provides a novel approach to assemble 2-carbonylethylindole skeletons. (Figure presented.).
Sequential asymmetric catalysis in Michael-Michael-Michael-aldol reactions: Merging organocatalysis with photoredox catalysis in a one-pot enantioselective synthesis of highly functionalized decalines bearing a quaternary carbon stereocenter
Hong, Bor-Cherng,Lin, Cheng-Wei,Liao, Wei-Kai,Lee, Gene-Hsiang
, p. 6258 - 6261 (2013)
An expedited method has been developed for the enantioselective synthesis of highly functionalized decaline systems containing seven contiguous stereogenic centers with high enantioselectivities (>99% ee). The one-pot methodology comprises a cascade of organocatalytic double Michael-photocatalyzed Michael-aldol reactions of ethyl 2-bromo-6-formylhex-2-enoate, β-alkyl-α,β-unsaturated aldehydes, and α-alkyl-α, β-unsaturated aldehydes. The structure and absolute configuration of an appropriate product were confirmed by X-ray analysis.
Rhodium-Catalyzed Regio- And Enantioselective Allylic Amination of Racemic 1,2-Disubstituted Allylic Phosphates
Li, Changkun,Shu, Mouhai,Sun, Minghe,Xu, Wen-Bin
supporting information, p. 8255 - 8260 (2021/06/27)
Alkynylphosphines are rarely used as ligands in asymmetric metal catalysis. We synthesized a series of chiral bis(oxazoline)alkynylphosphine ligands and used them in Rh-catalyzed highly regio- and enantioselective allylic amination reactions of 1,2-disubstituted allylic phosphates. Chiral 1,2-disubstituted allylic amines were synthesized in up to 95% yield with >20:1 branched/linear (b/l) ratio and 99% ee from racemic 1,2-disubstituted allylic precursors. The sterically smaller linear alkynyl group on the P atom in the bis(oxazoline)alkynylphosphine ligands was the key to fit the new requirements of the introduction of bulky 2-R′ groups.
Method for synthesizing alpha-methylcinnamaldehyde from phenylpropionaldehyde
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Paragraph 0011; 0036-0049, (2021/03/31)
The invention discloses a method for synthesizing alpha-methylcinnamaldehyde from phenylpropionaldehyde. The method comprises the following steps: 1) under the catalysis of alkali liquor, enabling phenylpropionaldehyde and an aqueous formaldehyde solution to pass through a continuous tank reactor, and conducting condensing to obtain a 2-benzylacrolein intermediate; and 2) carrying out hydroisomerization to obtain alpha-methylcinnamaldehyde. The raw materials, namely phenylpropionaldehyde and formaldehyde selected in the method are widely and readily available and low in price, so the method has a cost advantage; and the formaldehyde has good water solubility, the phenylpropionaldehyde is not easy to undergo the Cannizaro side reaction, and the intermediate prepared by condensation of the phenylpropionaldehyde and the phenylpropionaldehyde is easy to realize high yield.
Enantioselective hydroesterificative cyclization of 1,6-enynes to chiral γ-lactams bearing a quaternary carbon stereocenter
Dong, Kaiwu,Li, Huimin,Ren, Xinyi,Shen, Chaoren,Tang, Lin,Wang, Peng
supporting information, p. 3561 - 3566 (2021/05/29)
A palladium-catalyzed asymmetric hydroesterification-cyclization of 1,6-enynes with CO and alcohol was developed to efficiently prepare a variety of enantioenriched γ-lactams bearing a chiral quaternary carbon center and a carboxylic ester group. The approach featured good to high chemo-, region-, and enantioselectivities, high atom economy, and mild reaction conditions as well as broad substrate scope. The correlation between the multiple selectivities of such process and the N-substitutes of the amide linker in the 1,6-enyne substrate has been depicted by the crystallographic evidence and control experiments.
When Gold Meets Perfumes: Synthesis of Olfactive Compounds via Gold-Catalyzed Cycloisomerization Reactions
Laher, Romain,Marin, Christophe,Michelet, Véronique
supporting information, p. 4058 - 4062 (2020/04/20)
An efficient, and mild synthetic route for the preparation of functionalized volatile oxa-bicyclo[4.1.0]-hept-4-ene (29 compounds, 44-98% isolated yields) has been developed relying on the association of IPrAuCl with NaBArF. The remarkable selectivity was demonstrated on a 1 g and 25 g scale with low catalyst loadings. The synthetic utility of these low-molecular-weight enols was further demonstrated by the derivatization of some adducts and by the unprecedented olfactory evaluation of all bicyclic derivatives.
Nickel-Catalyzed Asymmetric Reductive 1,2-Carboamination of Unactivated Alkenes
He, Jun,Xue, Yuhang,Han, Bo,Zhang, Chunzhu,Wang, You,Zhu, Shaolin
supporting information, p. 2328 - 2332 (2020/01/08)
Starting from diverse alkene-tethered aryl iodides and O-benzoyl-hydroxylamines, the enantioselective reductive cross-electrophilic 1,2-carboamination of unactivated alkenes was achieved using a chiral pyrox/nickel complex as the catalyst. This mild, modular, and practical protocol provides rapid access to a variety of β-chiral amines with an enantioenriched aryl-substituted quaternary carbon center in good yields and with excellent enantioselectivities. This process reveals a complementary regioselectivity when compared to Pd and Cu catalysis.
Enantioselective Aza-Heck Cyclizations of N-(Tosyloxy)carbamates: Synthesis of Pyrrolidines and Piperidines
Ma, Xiaofeng,Hazelden, Ian R.,Langer, Thomas,Munday, Rachel H.,Bower, John F.
supporting information, p. 3356 - 3360 (2019/03/07)
Pd(0)-systems modified with SPINOL-derived phosphoramidate ligands promote highly enantioselective aza-Heck cyclizations of alkenyl N-(tosyloxy)carbamates. The method provides versatile access to challenging N-heterocycles and represents the broadest scope enantioselective aza-Heck protocol developed to date.
Exploration of Diverse Reactive Diad Geometries for Bifunctional Catalysis via Foldamer Backbone Variation
Girvin, Zebediah C.,Gellman, Samuel H.
supporting information, p. 12476 - 12483 (2018/09/27)
What is the best spatial arrangement of a pair of reactive groups for bifunctional catalysis of a chemical transformation? The conformational versatility of proteins allows reactive group geometry to be explored and optimized via evolutionary selection, but it has been difficult for chemists to identify synthetic scaffolds that allow broad comparative evaluation among alternative reactive group geometries. Here we show that a family of helices, adopted predictably by oligomers composed partially or exclusively of β-amino acid residues, enables us to explore a range of orientations for a pair of pyrrolidine units that must work in tandem to catalyze a crossed aldol reaction. Thus, the crossed aldol reaction serves as an assay of reactive diad efficacy. We have chosen a test reaction free of stereochemical complexity in order to streamline our study of reactivity. The best geometry enhances the initial rate of product formation by two orders of magnitude. Our findings raise the possibility that rudimentary catalysts involving an isolated secondary structure might have facilitated the development of prebiotic reaction networks.
Direct Access to Versatile Electrophiles via Catalytic Oxidative Cyanation of Alkenes
Gao, De-Wei,Vinogradova, Ekaterina V.,Nimmagadda, Sri Krishna,Medina, Jose M.,Xiao, Yiyang,Suciu, Radu M.,Cravatt, Benjamin F.,Engle, Keary M.
supporting information, p. 8069 - 8073 (2018/06/22)
Nucleophilic attack on carbon-based electrophiles is a central reactivity paradigm in chemistry and biology. The steric and electronic properties of the electrophile dictate its reactivity with different nucleophiles of interest, allowing the opportunity to fine-tune electrophiles for use as coupling partners in multistep organic synthesis or for covalent modification of proteins in drug discovery. Reactions that directly transform inexpensive chemical feedstocks into versatile carbon electrophiles would therefore be highly enabling. Herein, we report the catalytic, regioselective oxidative cyanation of conjugated and nonconjugated alkenes using a homogeneous copper catalyst and a bystanding N-F oxidant to furnish branched alkenyl nitriles that are difficult to prepare using existing methods. We show that the alkenyl nitrile products serve as electrophilic reaction partners for both organic synthesis and the chemical proteomic discovery of covalent protein ligands.
