Enantioselective and Regiodivergent Copper-Catalyzed Electrophilic Arylation of Allylic Amides with Diaryliodonium Salts.

A catalytic enantioselective and regiodivergent arylation of alkenes is described. Chiral copper(II)bisoxazoline complexes catalyze the addition of diaryliodonium salts to allylic amides in excellent ee. Moreover, the arylation can be controlled by the electronic nature of the diaryliodonium salt enabling the preparation of nonracemic diaryloxazines or β,β'-diaryl enamides.We are grateful to EPSRC, GSK and the University of Cambridge (E.C., H.P.J.M. & M.T.) and the ERC and EPSRC for fellowships (M.J.G.). Mass spectrometry data were acquired at the EPSRC UK National Mass Spectrometry Facility at Swansea University.This is the final version of the article. It first appeared from ACS via http://dx.doi.org/10.1021/jacs.5b0393

Reactions of a super-electron donor with diarylcyclopropanes and epoxides

The selective deoxygenation of both cis- and trans-isomers of 2,3-bis(4-fluorophenyl)oxirane, 2,3-bis(4-chlorophenyl)oxirane and 2,3-diphenyloxirane was achieved by the DMAP-derived electron donor 1.57 (Scheme 1). In each case, only the trans-alkene product was isolated. The reaction conditions depend on the energy level of the LUMO of the molecule. The higher the LUMO is, the harsher the conditions are. The use of UV-light was necessary to achieve reductive cleavage of the unsubstituted 2,3-diphenyloxiranes. In the case of 2,3-bis(4- chlorophenyl)oxirane, partial reductive cleavage of the aryl C-Cl bond was also observed. Dichloro- and monochlorostilbenes were isolated. However no monochlorinated oxirane was observed. Scheme 1 - Reactivity of epoxides with electron donor 1.57. The geometric isomerisation of diarylcyclopropanes was also achieved by DMAP-derived electron donor 1.57. Both geometric isomers of 1,2-bis(4-fluorophenyl)cyclopropane and 1,2- diphenylcyclopropane were isomerised when submitted to 1.57 (Scheme 2). However, no complete isomerisation was observed. These reactions required activation by UV-light. However, it has been proved that the isomerisation was not seen in the absence of donor 1.57, even if UV activation was used. Scheme 2 - Reactivity of 1,2-bis(4-fluorophenyl)cyclopropane and 1,2-diphenylcyclopropane with 1.57. N NMe2 N NMe2 1.57 7 A different reactivity was observed when submitting both geometric isomers of 1,2-bis(4- chlorophenyl)cyclopropane to the electron donor 1.57 (Scheme 3). Whereas in this case isomerisation of 1,2-bis(4-chlorophenyl)cyclopropane was mainly due to UV-light, the electron donor 1.57 was responsible for the cleavage of aryl C-Cl bonds giving rise to a complex mixture of both geometric isomers of di-, mono- and non-chlorinated diarylcyclopropanes. Scheme 3 - Reactivity of of 1,2-bis(4-chlorophenyl)cyclopropane with electron donor 1.57.The selective deoxygenation of both cis- and trans-isomers of 2,3-bis(4-fluorophenyl)oxirane, 2,3-bis(4-chlorophenyl)oxirane and 2,3-diphenyloxirane was achieved by the DMAP-derived electron donor 1.57 (Scheme 1). In each case, only the trans-alkene product was isolated. The reaction conditions depend on the energy level of the LUMO of the molecule. The higher the LUMO is, the harsher the conditions are. The use of UV-light was necessary to achieve reductive cleavage of the unsubstituted 2,3-diphenyloxiranes. In the case of 2,3-bis(4- chlorophenyl)oxirane, partial reductive cleavage of the aryl C-Cl bond was also observed. Dichloro- and monochlorostilbenes were isolated. However no monochlorinated oxirane was observed. Scheme 1 - Reactivity of epoxides with electron donor 1.57. The geometric isomerisation of diarylcyclopropanes was also achieved by DMAP-derived electron donor 1.57. Both geometric isomers of 1,2-bis(4-fluorophenyl)cyclopropane and 1,2- diphenylcyclopropane were isomerised when submitted to 1.57 (Scheme 2). However, no complete isomerisation was observed. These reactions required activation by UV-light. However, it has been proved that the isomerisation was not seen in the absence of donor 1.57, even if UV activation was used. Scheme 2 - Reactivity of 1,2-bis(4-fluorophenyl)cyclopropane and 1,2-diphenylcyclopropane with 1.57. N NMe2 N NMe2 1.57 7 A different reactivity was observed when submitting both geometric isomers of 1,2-bis(4- chlorophenyl)cyclopropane to the electron donor 1.57 (Scheme 3). Whereas in this case isomerisation of 1,2-bis(4-chlorophenyl)cyclopropane was mainly due to UV-light, the electron donor 1.57 was responsible for the cleavage of aryl C-Cl bonds giving rise to a complex mixture of both geometric isomers of di-, mono- and non-chlorinated diarylcyclopropanes. Scheme 3 - Reactivity of of 1,2-bis(4-chlorophenyl)cyclopropane with electron donor 1.57

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ISSN:0272-1708ISSN:1066-033XISSN:1941-000

Reserach data supporting "Enantioselective and regiodivergent copper-­catalyzed electrophilic arylation of allylic amides with diaryliodonium salts - SI"

Supplementary experimental information describing general laboratory information, preparation of starting materials and conditions for the preparation of the desired products of this novel methodology.The article associated with this dataset has been published by ACS at http://pubs.acs.org/doi/abs/10.1021/jacs.5b03937. A version of the article can also be found on the Cambridge University Repository at https://www.repository.cam.ac.uk/handle/1810/249245.This work was supported by the ERC, the EPSRC and GSK

Reductions of Challenging Organic Substrates by a Nickel Complex of a Noninnocent Crown Carbene Ligand

The first crown-tetracarbene complex of Ni(II) has been prepared, and its crystal structure determined. The complex can be reduced by Na/Hg, with an uptake of two electrons. The reduced complex reductively cleaves arenesulfonamides, including those derived from secondary aliphatic amines, and effects Birch reduction of anthracenes as well as reductive cleavage of stilbene oxides. Computational studies show that the orbital that receives electrons upon reduction of the complex <b>2</b> is predominantly based on the crown carbene ligand and also that the HOMO of the parent complex <b>2</b> is based on the ligand

Reductions of Challenging Organic Substrates by a Nickel Complex of a Noninnocent Crown Carbene Ligand

The first crown-tetracarbene complex of Ni(II) has been prepared, and its crystal structure determined. The complex can be reduced by Na/Hg, with an uptake of two electrons. The reduced complex reductively cleaves arenesulfonamides, including those derived from secondary aliphatic amines, and effects Birch reduction of anthracenes as well as reductive cleavage of stilbene oxides. Computational studies show that the orbital that receives electrons upon reduction of the complex <b>2</b> is predominantly based on the crown carbene ligand and also that the HOMO of the parent complex <b>2</b> is based on the ligand

Reductions of challenging organic substrates by a nickel complex of a noninnocent crown carbene ligand

The first crown-tetracarbene complex of Ni(II) has been prepared, and its crystal structure determined. The complex can be reduced by Na/Hg, with an uptake of two electrons. The reduced complex reductively cleaves arenesulfonamides, including those derived from secondary aliphatic amines, and effects Birch reduction of anthracenes as well as reductive cleavage of stilbene oxides. Computational studies show that the orbital that receives electrons upon reduction of the complex 2 is predominantly based on the crown carbene ligand and also that the HOMO of the parent complex 2 is based on the ligand