The term organocatalysis describes the acceleration of chemical reactions through the addition of a substoichiometric quantity of an organic compound. The interest in this field has increased spectacularly in the last few years as result of both the novelty of the concept and, more importantly, the fact that the efficiency and selectivity of many organocatalytic reactions meet the standards of established organic reactions. Organocatalytic reactions are becoming powerful tools in the construction of complex molecular skeletons.[1,2]
 Special issue of Adv. Synth. Catal. 2004, 346, Nr. 9-10.
An organic acid catalyzed direct arylation of aromatic C(sp2)H bonds in phenols and naphthols was developed. This transformation is operationally simple, does not require an external oxidant, is readily scaled up, and the structurally diverse biaryls are formed with complete regioselectivity. Density functional calculations suggest a mechanism involving a mixed-acetal formation/[3,3]-sigmatropic rearrangement sequence.
Hongyin Gao, Qing-Long Xu, Craig Keene, Muhammed Yousufuddin, Daniel H. Ess, László Kürti
Angew. Chem. Int. Ed., November 23, 2015, DOI: 10.1002/anie.201508419. Read article
We have developed a photocatalytic CAr–Rf bond formation reaction by homolytic aromatic substitution (HAS) with an inexpensive organic dye, Rose Bengal, in the absence of transition metals, through irradiation at ambient temperature with visible light by using readily available perfluoroalkyl halides. This method was applied to the synthesis of a variety of perfluoroalkyl-substituted aniline derivatives.
Sebastián Barata-Vallejo, Damian E. Yerien, Al Postigo
Eur. J. Org. Chem., November 18, 2015, DOI: 10.1002/ejoc.201501189. Read article.
Paired off: The title reaction leads to effective resolution of a wide range of β-sulfonyl ketones (1) with high stereoselectivity. Key to the success of this process is the favorable secondary interactions of the catalyst with the Lewis basic groups on the substrate. The enone product can be easily converted into the racemic starting material and allows effective recycling, and thus isolation of β-sulfonyl ketones in high yield and excellent enantioselectivity.
Liang Li, Yidong Liu, Yang Peng, Lei Yu, Xiaoyan Wu, Hailong Yan
Angew. Chem. Int. Ed., November 18, 2015, DOI: 10.1002/anie.201508127. Read article
The design of synthetic protocols for promising and useful organic reactions at ambient conditions coupled with other green aspects is of current interest in the field of green chemistry practice. The present account summarizes our sincere efforts in designing green synthetic protocols for diverse organic transformations at room temperature and pressure reported during the last five years.
The Chemical Record, November 17, 2015, DOI: 10.1002/tcr.201500229. Read article
“Gummy bear”-like hydrogels for the immobilization of organocatalysts: With embedding of benzoylcupreine in a PIL-based hydrogel, the catalyst was reused for four cycles after the Henry reaction without loss of enantioselectivity (up to 91 % ee).
Julia Großeheilmann, Jenny Bandomir, Udo Kragl
Chem. Eur. J., November 16, 2015, DOI: 10.1002/chem.201504290. Read article.
A chiral spiro-phosphoric-acid-catalyzed asymmetric approach for constructing the biologically important cyclopenta[1,4]diazepine scaffold with high enantioselectivity (up to 98:2 er) has been established through the use of three-component tandem reactions of cyclopentane-1,3-dione, 1,2-phenylenediamine, and isatins under mild reaction conditions.
Meng Sun, Yang Wang, Lei Yin, Yang-Yan Cao, Feng Shi
Eur. J. Org. Chem., November 13, 2015, DOI: 10.1002/ejoc.201501255. Read article.
Pure and simple: Organic solvent nanofiltration proves to be an efficient alternative to column chromatography for the purification of quinine-based organocatalysts. These catalysts are obtained in a high purity of >99 % after 10 discontinuous diafiltration steps. c c0−1: residual concentration, VD V0−1: number of volume exchanges
Julia Großeheilmann, Thomas Fahrenwaldt, Udo Kragl
ChemCatChem, November 12, 2015, DOI: 10.1002/cctc.201500902. Read article
Chiral quaternary carbon stereocenters were constructed in an enantioselective 1,4-addition reaction of acyclic 2-formyl(thio)esters to vinylketones catalyzed by thiourea-tertiary amine containing a bulky chiral backbone with high enantioselectivity (up to 96 % ee). Derivatization of the adducts was also performed to obtain several less-accessible compounds bearing a chiral quaternary carbon stereocenter.
Toshifumi Tatsumi, Tomonori Misaki, Takashi Sugimura
Chem. Eur. J., Nov 11, 2015, DOI: 10.1002/chem.201504479. Read article.
Tip the balance: Enantioselective 1,2-type Friedel–Crafts reaction of phenols with N-tert-butoxycarbonyl aldimines catalyzed by conformationally flexible guanidine bisthioureas proceeded with large differential activation entropy (see figure).
Masaru Kato, Shogo Hirao, Katsuhiro Nakano, Makoto Sato, Masahiro Yamanaka, Yoshihiro Sohtome, Kazuo Nagasawa
Chem. Eur. J., November 6, 2015, DOI: 10.1002/chem.201503280. Read article.
Highly efficient chiral sulfinamide bisphosphine catalysts (Wei-Phos, 1) were developed that could be easily prepared from commercially available starting materials. Wei-Phos has shown good performance in the intermolecular cross-Rauhut–Currier reactions of vinyl ketones and 3-acyl acrylates or 2-ene-1,4-diones, leading to products in high yields with up to 99 % ee under 2.5–5.0 mol% catalyst loading.
Wei Zhou, Xiao Su, Mengna Tao, Chaoze Zhu, Qingjie Zhao, Junliang Zhang
Angew. Chem. Int. Ed., November 03, 2015, DOI: 10.1002/anie.201508108. Read article
Undiluted catalytic power: Supported bifunctional thioureas, prepared by a bottom-up methodology, promote highly enantioselective aza-Henry and nitro-Michael reactions under solvent-free conditions (see scheme; Boc=tert-butyloxycarbonyl, d.r.=diastereomeric ratio, e.r.=enantiomeric ratio).
José M. Andrés, Noelia de La Cruz, María Valle, Rafael Pedrosa
ChemPlusChem, November 02, 2015, DOI: 10.1002/cplu.201500476. Read article
Complex and diverse: The microwave-assisted rearrangement of propargyl vinyl ethers in the presence of a catalytic amount of imidazole generates topologically complex salicylaldehyde derivatives adorned with diverse and varied substitution patterns (see scheme).
David Tejedor, Leandro Cotos, Daniel Márquez-Arce, Mikel Odriozola-Gimeno, Miquel Torrent-Sucarrat , Fernando P. Cossío, Fernando García-Tellado
Chem. Eur. J., October 30, 2015, DOI: 10.1002/chem.201503171. Read article.
Reaction-based mechanistic investigations were performed for the hetero-Diels-Alder (hDA) reactions of enones with isatins that were catalyzed by an amine-based catalyst system composed of three molecules (an amine, an acid, and a thiourea). The results indicated that the hDA product obtained from the reaction between hept-3-en-2-one and isatin under the amine-based three-component catalyst system was generated via a kinetically controlled [4 + 2] cycloaddition reaction of the in situ-generated enamine of the enone as the diene and isatin as the dienophile. The amine of the three-component catalyst system was essential for the catalysis and stereocontrol, but the other components of the catalyst system also played important roles. Based on the results, plausible transition states are discussed, and the catalyst system was further improved by altering the loadings of the catalyst components for faster reactions with high stereoselectivities.
Hai-Lei Cui, Pandurang V Chouthaiwale, Feng Yin, Fujie Tanaka
Asian J. Org. Chem., October 28, 2015, DOI: 10.1002/ajoc.201500412. Read article
Piecing it together: Recent advances in organocatalytic kinetic resolution by using small organic catalysts to resolve various racemates are described. The combination of sequential reaction processes and organocatalytic kinetic resolution enables the functionalization of products for further elaboration and recovery of less kinetically favored substrates to maximize atom economy.
Ramani Gurubrahamam, You-Song Cheng, Wan-Yun Huang, Kwunmin Chen
ChemCatChem, October 27, 2015, DOI: 10.1002/cctc.201500455. Read article
A tale of two rings: The N-heterocyclic carbene (NHC) catalyzed redox formal [2+2] cycloaddition between α-aroyloxyaldehydes and perfluoroketones, followed by ring-opening in situ delivers a variety of perfluorinated β-hydroxycarbonyl compounds in good yield, and excellent diastereo- and enantioselectivity. Through a reductive work-up and subsequent cyclization, this protocol offers access to highly substituted fluorinated oxetanes in two steps and in high ee.
Alyn T. Davies, Alexandra M. Z. Slawin, Andrew D. Smith
Chem. Eur. J., Oct 26, 2015, DOI: 10.1002/chem.201504256. Read article.
Programmed death: The highly enantioselective preparation of pharmacologically interesting hexahydropyridazine derivatives is described. Mechanistic studies performed on one of these derivatives suggest that they exert anticancer effects by inducing apoptosis through extracellular signal related kinase (ERK)- and poly(adenosine diphosphate ribose) polymerase (PARP)-regulated pathways, as well as mitochondrial pathways (see figure).
Hai-Jun Leng, Fu Peng, Sarah Zingales, Wei Huang, Biao Wang, Qian Zhao, Rui Zhou, Gu He, Cheng Peng, Bo Han
Chem. Eur. J., October 26, 2015, DOI: 10.1002/chem.201503063. Read article.
A real square cat.: Thirteen different 1,3-dinitro compounds were synthesized with excellent enantioselectivity (up to 95 % ee) and high diastereoselectivity (syn/anti isomers up to 96:4) by using 2 mol % of a chiral bifunctional quinine squaramide-based organocatalyst in the enantioselective Michael addition of nitroalkanes to nitroalkenes.
Esra Kanberoğlu, Cihangir Tanyeli
Asian J. Org. Chem., October 26, 2015, DOI: 10.1002/ajoc.201500339. Read article
Three for the price of 2: Asymmetric organocatalytic methods for the synthesis of axially, planar, and helical chiral compounds as useful chiral building blocks are summarized. Unique synthetic strategies have been demonstrated to obtain these chiral compounds with high stereoselectivities.
Seiji Shirakawa, Shiyao Liu, Shiho Kaneko
Chem. Asian J., October 15, 2015, DOI: 10.1002/asia.201500951. Read article
An intermolecular asymmetric dearomatization reaction of β-naphthols with nitroethylene through a chiral-thiourea-catalyzed Michael reaction is described. Enantioenriched functionalized β-naphthalenones with an all-carbon quaternary stereogenic center were easily constructed in good yields and excellent enantioselectivity (up to 79 % yield, 98 % ee).
Shou-Guo Wang, Xi-Jia Liu, Qun-Chao Zhao, Chao Zheng, Shao-Bo Wang, Shu-Li You
Angew. Chem. Int. Ed., October 14, 2015, DOI: 10.1002/anie.201507998. Read article
Being picky: A direct, concise, and enantioselective synthesis of 2-substituted 4,4,4-trifluorobutane-1,3-diols based on the organocatalytic asymmetric direct aldol reaction of an ethyl hemiacetal of trifluoroacetaldehyde with various aldehydes is described (see scheme).
Kazumasa Funabiki, Yudai Furuno, Yosuke Yano, Yuta Sakaida, Yasuhiro Kubota, Masaki Matsui
Chem. Asian J., August 17, 2015, DOI: 10.1002/asia.201500607. Read article
Carbo loading: Herein we report a short and efficient protocol for the synthesis of naturally occurring higher-carbon sedoheptulose (d-altro-hept-2-ulose) and d-glycero-l-galacto-oct-2-ulose from readily available sugar aldehydes and dihydroxyacetone (DHA). The key step includes a diastereoselective organocatalytic syn-selective aldol reaction of DHA with d-erythrose and d-xylose, respectively.
Oskar Popik, Monika Pasternak-Suder, Sebastian Baś, Jacek Mlynarski
ChemistryOpen, June 26, 2015, DOI: 10.1002/open.201500099. Read article
Douglass F. Taber
Isr. J. Chem., April 15, 2015, DOI: 10.1002/ijch.201500006. Read article