Academic literature on the topic 'Copper catalysts. Olefines'

Paul J. Chirik at Princeton University reported (Science 2012, 335, 567) an iron catalyst that hydrosilylates alkenes with anti-Markovnikov selectivity, as in the conversion of 1 to 2. A regioselective hydrocarbamoylation of terminal alkenes was developed (Chem. Lett. 2012, 41, 298) by Yoshiaki Nakao at Kyoto University and Tamejiro Hiyama at Chuo University, which allowed for the chemoselective conversion of diene 3 to amide 4. Gojko Lalic at the University of Washington reported (J. Am. Chem. Soc. 2012, 134, 6571) the conversion of terminal alkenes to tertiary amines, such as 5 to 6, with anti-Markovnikov selectivity by a sequence of hydroboration and copper-catalyzed amination. Related products such as 8 were prepared (Org. Lett. 2012, 14, 102) by Wenjun Wu at Northwest A&F University and Xumu Zhang at Rutgers via an isomerization-hydroaminomethylation of internal olefin 7. Seunghoon Shin at Hanyang University (experimental work) and Zhi-Xiang Yu at Peking University (computational work) reported (J. Am. Chem. Soc. 2012, 134, 208) that 9 could be directly converted to bicyclic lactone 11 with propiolic acid 10 using gold catalysis. A nickel/Lewis acid multicatalytic system was found (Angew. Chem. Int. Ed. 2012, 51, 5679) by the team of Professors Nakao and Hiyama to effect the addition of pyridones to alkenes, such as in the conversion of 12 to 13. Radical-based functionalization of alkenes using photoredox catalysis was developed (J. Am. Chem. Soc. 2012, 134, 8875) by Corey R.J. Stephenson at Boston University, an example of which was the addition of bromodiethyl malonate across alkene 14 to furnish 15. Samir Z. Zard at Ecole Polytechnique reported (Org. Lett. 2012, 14, 1020) that the reaction of xanthate 17 with terminal alkene 16 led to the product 18. The radical-based addition of nucleophiles including azide to alkenes with Markovnikov selectivity (cf. 19 to 20) was reported (Org. Lett. 2012, 14, 1428) by Dale L. Boger at Scripps La Jolla using an Fe(III)/NaBH4-based system. A remarkably efficient and selective catalyst 22 was found (J. Am. Chem. Soc. 2012, 134, 10357) by Douglas B. Grotjahn at San Diego State University for the single position isomerization of alkenes, which effected the transformation of 21 to 23 in only half an hour.

It is thought that the pseudopterane class of diterpenoid natural products, of which 11-gorgiacerol is a member, arises biosynthetically by a photo-ring contraction of the related furanocembranes. Johann Mulzer at the University of Vienna has applied (Org. Lett. 2012, 14, 2834) this logic to realize the total synthesis of 11-gorgiacerol. Ringclosing metathesis of the butenolide 1 using the Grubbs second generation catalyst produced the tricycle 2. When irradiated, 2 undergoes a 1,3-rearrangement to furnish the natural product in good yield. Whether this rearrangement is concerted, or occurs stepwise via a diradical intermediate, is not known. Although ring-closing metathesis has become a reliable method for macrocycle construction, its use here to set what then becomes an extracyclic olefin is notable. Berkelic acid is produced by an extremophile bacterium penicillium species that lives in the toxic waters of an abandoned copper mine, and this natural product has been found to possess some very intriguing biological activities. Not surprisingly, berkelic acid has attracted significant attention from synthetic chemists, including Francisco J. Fañanás of Universidad de Oviedo in Spain, who has developed (Angew. Chem. Int. Ed. 2012, 51, 4930) a scalable, protecting-group free total synthesis. The key step in this route is the remarkable silver(I)-catalyzed coupling of alkyne 3 and aldehyde 4 to produce, after hydrogenation, the structural core 5 of (–)-berkelic acid on a gram scale. Some tools from the field of organocatalysis have been brought to bear (Angew. Chem. Int. Ed. 2012, 51, 5735) on a new total synthesis of the macrolide (+)-dactylolide by Hyoungsu Kim of Ajou University in Korea and Jiyong Hong of Duke University. The bridging tetrahydropyranyl ring is fashioned by way of an intramolecular 1,6-oxa conjugate addition of dienal 6 to produce 8 under catalysis by the secondary amine 7. Following some synthetic manipulations, the macrocyclic ring 12 is subsequently forged by an NHC-catalyzed oxidative macrolactonization using the carbene catalyst 10 and diphenoquinone 11 as the oxidant. A new approach to the nanomolar antimitotic agent spirastrellolide F methyl ester has been reported (Angew. Chem. Int. Ed. 2012, 51, 8739) by Alois Fürstner of the Max-Planck-Institut, Mülheim. Two elegant metal-catalyzed processes form the key basis of this strategy.

Huanfeng Jiang at the South China University of Technology developed (J. Am. Chem. Soc. 2013, 135, 5286) the palladium-catalyzed dehydrogenative aminohalogenation of methyl acrylate with aniline 1. A 1,3-hydrogen shift/ chlorination catalyzed by an iridium complex was reported (Angew. Chem. Int. Ed. 2013, 52, 6273) by Belén Martín- Matute at Stockholm University. Robert M. Waymouth discovered (J. Am. Chem. Soc. 2013, 135, 7593) the chemoselective oxidation of polyol 5 by a cationic palladium species. A ruthenium(II) hydride was found to catalyze the conversion of alcohols such as 7 to carboxylic acids using water as the oxygen source as disclosed (Nature Chem. 2013, 5, 122) by David Milstein at the Weizmann Institute of Science in Israel. Susan K. Hanson at the Los Alamos National Laboratory in New Mexico reported (Org. Lett. 2013, 15, 650) the acceptorless dehydrogenation of alcohols catalyzed by cobalt complex 12 to form imines such as 13 upon reaction with an amine. A collabo­ration led by Pedro J. Pérez at the University of Huelva in Spain studied (J. Am. Chem. Soc. 2013, 135, 3887) the oxidation of alkanes under catalysis with copper complex 15, primarily yielding alcohols and ketones, such as in the conversion of cyclohexane (14) to cyclohexanol (16) and cyclohexanone (17). A remarkable symmetry-breaking Wacker oxidation of diene 18 to produce 19 was the key step in the total synthesis of (+)-obolactone reported (Org. Lett. 2013, 15, 1294) by Reinhard Brückner at the University of Freiburg in Germany. Kiyotomi Kaneda at the University of Osaka found (Angew. Chem. Int. Ed. 2013, 52, 5961) that a palladium salt catalyzes the conversion of electron-deficient internal olefin 20 to ketone 21. As part of a program to develop environmentally sustainable procedures, Caterina Fusco at the University of Bari in Italy described (Tetrahedron Lett. 2013, 54, 515) the oxidative cleavage of lactam 22 by methyl(trifluoromethyl)dioxirane in water to pro­duce ω-nitro acid 24. Motomu Kanai at the University of Tokyo reported (Org. Lett. 2013, 15, 1918) the β-functionalization of tertiary aromatic amine 25 with nitroolefin 26 to produce 27 by iron catalysis.

Andrew G. Myers at Harvard reported (Angew. Chem. Int. Ed. 2012, 51, 4568) the alkylation of the pseudophenamine amide 1 selectively setting the quaternary stereogenic center of 2. This is an effective replacement for his previously reported pseudoephedrine, now a controlled substance. Amine catalysis has enabled numerous methods for the asymmetric α-functionalization of aldehydes, although α-alkylation remains a significant challenge. David W.C. MacMillan at Princeton developed (J. Am. Chem. Soc. 2012, 134, 9090) an α-vinylation of aldehydes 3 with vinyliodoniums 5, which relied on the “synergistic combination” of the amine catalyst 4 and copper(I) bromide. The stability of the β,γ-unsaturated aldehyde products under the reaction conditions is notable. A procedure for the asymmetric β-vinylation of α,β-unsaturated aldehydes such as 7 was developed (Eur. J. Org. Chem. 2012, 2774) by Claudio Palomo at the Universidad del Pais Vasco in Spain. Amine 8 catalyzed the enantioselective Michael addition of β-nitroethyl sulfone 9 to 7 followed by acetalization and elimination of HNO2 and SO2Ph furnished products such as 10 in high enantiomeric excess. In a conceptually related reaction, a surrogate for acetate as a nucleophile was reported (Chem. Commun. 2012, 48, 148) by Wei Wang at the University of New Mexico and Jian Li of the East China University of Science and Technology. In this case, amine 13-catalyzed Michael addition of pyridyl sulfone 11 to unsaturated aldehyde 12, followed by acetalization and reductive removal of the sulfone, gave rise to the ester product 14 with very high ee. Asymmetric hydroformylation offers a powerful approach for the synthesis of carbon stereocenters, but controlling the regioselectivity of the reaction remains a challenge with many substrate classes. Christopher J. Cobley of Chirotech Technology Ltd. (UK) and Matthew L. Clarke at the University of St. Andrews showed (Angew. Chem. Int. Ed. 2012, 51, 2477) that the mixed phosphine-phosphite ligand “bobphos” 16 (bobphos = best of both phosphorus ligands) provided significant selectivities for the branched hydroformylation products, up to 10:1 b:l in the case of 15. Another major challenge for hydroformylation is to control the regioselectivity of internal olefin substrates.