871707-40-3Relevant academic research and scientific papers
First modular synthesis of dissymmetric biaryldiphosphine ligands allowing tunable steric and electronic effects
Leroux, Frederic R.,Mettler, Hanspeter
, p. 323 - 336 (2008/02/07)
The first modular synthesis of a family of C1-symmetric diphosphine ligands is presented. Their synthesis is based on unprecedented highly regioselective halogen/metal interconversions on a common polybrominated biaryl precursor. This methodology allows the functionalization of the ortho- and ortho'-positions of the biaryl core. Diphosphine ligands carrying only one substituent at the 6-position and the two phosphine substituents at the 2- and 2′-position become easily accessible. The two phosphine substituents may be identical (as in compounds 2 and 3) or different (as in compounds 1 and 4). All diphosphines were prepared on gram scale, and the enantiopure ligands were obtained by chromatography of the racemate on a chiral HPLC column. The asymmetric hydrogenation of β-keto esters, acetamidocinnamates and dimethyl itaconate revealed good to excellent asymmetric inductions of up to 99 % ee, and are often close to those of the well-known C2-symmetric MeO-BIPHEP.
Ligand tailoring: The first modular assembly of atropisomeric biarylbisphosphine ligands
Leroux, Frédéric,Mettler, Hanspeter
, p. 766 - 770 (2007/10/03)
Strategies based on highly selective halogen-metal permutations have been devised and applied enabling the modular assembly of atropisomeric biaryl bisphosphines. After resolution on chiral column, the ligands were tested in benchmark hydrogenation reactions affording good to excellent enantioselectivity. Georg Thieme Verlag Stuttgart.
Process for the preparation of asymmetrically substituted biaryldiphosphines
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Page/Page column 12, (2010/02/15)
Provided is a process for the preparation of asymmetrically substituted biaryldiphosphine ligands of the formula wherein R1 is C1-6-alkyl or C3-10-cycloalkyl optionally being substituted with one or more halogen atoms, and R2 and R3 are independently selected from the group consisting of aryl, C5-10-cycloalkyl and C1-6-alkyl, wherein each aryl moiety is optionally substituted with one or more substituents selected from the group consisting of halogen atoms, nitro, amino, C1-6-alkyl, C1-6-alkoxy and di-C1-6-alkylamino groups, and each C1-6-alkyl, C1-6-alkoxy, di-C1-6-alkylamino and C5-10-cycloalkyl group in R2 and R3 optionally being substituted with one or more halogen atoms, from 2,2',6,6'-tetrabromobiphenyl by a sequence of halogen-metal exchanges and subsequent reactions.
