Showing papers by "David A. Nicewicz published in 2013"
TL;DR: In this paper, the metal-free H-atom donor for trifluoromethanesulfinate alkenes is presented, which relies on the single electron oxidation of a commercially available triflooromethane sulfinate salt (CF3SO2Na, Langlois reagent) by N-Me-9-mesityl acridinium as a photoredox catalyst.
Abstract: Herein is presented a direct method for the metal-free hydrotrifluoromethylation of alkenes. The method relies on the single electron oxidation of a commercially available sodium trifluoromethanesulfinate salt (CF3SO2Na, Langlois reagent) by N-Me-9-mesityl acridinium as a photoredox catalyst. Methyl thiosalicylate is used as a substoichiometric H-atom donor for aliphatic alkenes, and thiophenol is used as a stoichiometric H-atom donor for styrenyl substrates. The substrate scope for the transformation is broad, including mono-, di- and trisubstituted aliphatic and styrenyl alkenes, with high regioselectivity in nearly all cases examined.
349 citations
TL;DR: Iradiation of the amine substrates with visible light in the presence of catalytic quantities of easily synthesized 9-mesityl-10-methylacridinium tetrafluoroborate and thiophenol as a hydrogen-atom donor furnished the nitrogen-containing heterocycles with complete regiocontrol.
Abstract: Herein we report a metal-free method for the direct anti-Markovnikov hydroamination of unsaturated amines. Irradiation of the amine substrates with visible light in the presence of catalytic quantities of easily synthesized 9-mesityl-10-methylacridinium tetrafluoroborate and thiophenol as a hydrogen-atom donor furnished the nitrogen-containing heterocycles with complete regiocontrol. Two examples of intermolecular anti-Markovnikov alkene hydroamination are also disclosed.
235 citations
TL;DR: A direct catalytic anti-Markovnikov addition of carboxylic acids to alkenes is reported, and a deuterium-labeling experiment lends insight to the potential mechanism.
Abstract: A direct catalytic anti-Markovnikov addition of carboxylic acids to alkenes is reported. The catalyst system is comprised of the Fukuzumi acridinium photooxidant (1) and a substoichiometric quantity of a hydrogen-atom donor. Oxidizable olefins, such as styrenes, trisubstituted aliphatic alkenes, and enamides, can be employed along with a variety of carboxylic acids to afford the anti-Markovnikov addition adducts exclusively. A deuterium-labeling experiment lends insight to the potential mechanism.
155 citations
TL;DR: This method has been adapted to the synthesis of the natural products magnosalin and pellucidin A and key to minimizing competing cycloreversion is the inclusion of an aromatic electron relay (ER).
Abstract: A direct method to synthesize lignan cyclobutanes and analogs via photoinduced electron transfer is presented. A variety of oxygenated alkenes are employed to furnish terminal or substituted cyclobutane adducts with complete regiocontrol, yielding cycloadducts with trans stereochemistry. Key to minimizing competing cycloreversion is the inclusion of an aromatic electron relay (ER). This method has been adapted to the synthesis of the natural products magnosalin and pellucidin A.
127 citations
TL;DR: An organic photoredox catalytic system for the direct intramolecular anti-Markovnikov hydroetherification of alkenols that produces fiveto seven-membered cyclic ethers with complete regiocontrol is established.
Abstract: The products are isolated as inseparable mixtures of diastereomers, some also containing traces of additional diastereomers not shown in the scheme.
125 citations
TL;DR: In this article, a direct intramolecular anti-Markovnikov hydroetherification reaction of alkenols is described using catalytic quantities of commercially available 9-mesityl-10-methylacridinium perchlorate and 2-phenylmalononitrile as a redox-cycling source of a H-atom.
Abstract: A direct intramolecular anti-Markovnikov hydroetherification reaction of alkenols is described. By employing catalytic quantities of commercially available 9-mesityl-10-methylacridinium perchlorate and 2-phenylmalononitrile as a redox-cycling source of a H-atom, we report the anti-Markovnikov hydroetherification of alkenes with complete regioselectivity. In addition, we present results demonstrating that this novel catalytic system can be applied to the anti-Markovnikov hydrolactonization of alkenoic acids.
26 citations
TL;DR: In this paper, a direct catalytic anti-Markovnikov addition of carboxylic acids to alkenes is reported, where the catalyst system is comprised of the Fukuzumi acridinium photooxidant and a substoichiometric quantity of a hydrogen-atom donor.
Abstract: A direct catalytic anti-Markovnikov addition of carboxylic acids to alkenes is reported. The catalyst system is comprised of the Fukuzumi acridinium photooxidant (1) and a substoichiometric quantity of a hydrogen-atom donor. Oxidizable olefins, such as styrenes, trisubstituted aliphatic alkenes, and enamides, can be employed along with a variety of carboxylic acids to afford the anti-Markovnikov addition adducts exclusively. A deuterium-labeling experiment lends insight to the potential mechanism.
9 citations
TL;DR: The photochemical reaction of the amine substrates does not require any metal catalyst and is effective in the presence of 9-mesityl-10-methylacridinium tetrafluoroborate and thiophenol as a hydrogen donor.
Abstract: The photochemical reaction of the amine substrates does not require any metal catalyst and is effective in the presence of 9-mesityl-10-methylacridinium tetrafluoroborate and thiophenol as a hydrogen donor.
6 citations
TL;DR: In this article, the metal-free H-atom donor for trifluoromethanesulfinate alkenes is presented, which relies on the single electron oxidation of a commercially available triflooromethane sulfinate salt (CF3SO2Na, Langlois reagent) by N-Me-9-mesityl acridinium as a photoredox catalyst.
Abstract: Herein is presented a direct method for the metal-free hydrotrifluoromethylation of alkenes. The method relies on the single electron oxidation of a commercially available sodium trifluoromethanesulfinate salt (CF3SO2Na, Langlois reagent) by N-Me-9-mesityl acridinium as a photoredox catalyst. Methyl thiosalicylate is used as a substoichiometric H-atom donor for aliphatic alkenes, and thiophenol is used as a stoichiometric H-atom donor for styrenyl substrates. The substrate scope for the transformation is broad, including mono-, di- and trisubstituted aliphatic and styrenyl alkenes, with high regioselectivity in nearly all cases examined.
5 citations
TL;DR: In this paper, the photolytic dimerization of methoxy substituted styrenes is studied using an oxopyrylium salt as the catalyst as well as a variety of electron relay additives.
Abstract: The photolytic dimerization of methoxy substituted styrenes is studied using an oxopyrylium salt as the catalyst as well as a variety of electron relay additives.
3 citations
Patent•
06 May 2013TL;DR: In this article, a method of making an anti-Markovnikov addition product is carried out by reacting an acid with an alkene or alkyne in a dual catalyst reaction system to the exclusion of oxygen to produce said anti-markovnik addition product; the dual catalyst system comprising a single electron oxidation catalyst in combination with a hydrogen atom donor catalyst.
Abstract: A method of making an anti-Markovnikov addition product is carried out by reacting an acid with an alkene or alkyne in a dual catalyst reaction system to the exclusion of oxygen to produce said anti-Markovnikov addition product; the dual catalyst reaction system comprising a single electron oxidation catalyst in combination with a hydrogen atom donor catalyst. Compositions useful for carrying out such methods are also described.
TL;DR: The products are isolated as inseparable mixtures of diastereomers, some also containing traces of additional diastereromers not shown in the scheme as mentioned in this paper, and some also contain traces of unknown diasteromers.
Abstract: The products are isolated as inseparable mixtures of diastereomers, some also containing traces of additional diastereomers not shown in the scheme.