P-Alkylated (1S,2S)-Cyclopentane-1,2-diylbisphosphanes with Four Stereogenic Centers and Some Group 10 Metal(II) Complexes Containing the (1S,2S)-C5H8[P(CH3)C8H15-cyclo]2 Ligand

(1S,2S)-Cyclopentane-1,2-diyl-bis(phosphonous dichloride), (1S,2S)-C5H8(PCl2)2 – A Versatile Optically Active Reagent

“…Our current research in this field has been focused on the development of variable methods of synthesis for more versatile (1S,2S)-C 5 H 8 (PCl 2 ) 2 (2). Actually, bis(phosphonous dichloride) 2 formed smoothly when bis(primary chiral bidentate phosphorus ligands with electron-rich and/ or electron-poor donor atoms, starting from the resolved phosphane) 1 and OC(OCCl 3 ) 2 where combined in THF at 50°C in 3:4 stoichiometry, as required for the quantitative enantiomers of chiral bis(primary phosphanes) [3] [4] . We herein report the details of a synthetic procedure that allows transformation of the two ϪPH 2 groups into ϪPCl 2 functions.…”

Regioselective versus complete chalcogen transfer reactions of the bis(bidentate) phosphine cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane: full characterization of new, hemilabile ligands and their complexes with palladium(ii) and platinum(ii)

“…45 The chirality of 1-6 is also a desirable feature. 50 Our future studies will focus on the catalytic applications of these systems.…”

P‐Modular Homochiral Bis(phosphanes) with 1,2‐Disubstituted Cyclopentane Backbones in Asymmetric Hydrogenation

“…In the first step of the synthesis leading to the C , P ‐chirogenic bis(phosphanes) L Me/R , which are to be regarded as conformationally rigid counterparts of Imamoto’s “( S P , S P′ )‐bisP*” ligands 1,2‐C 2 H 4 {( S )‐P(Me)R} 2 (R = i Pr, t Bu, Et 3 C, c C 5 H 9 , c C 6 H 11 , c C 6 H 10 Me, 1‐adamantyl),39 a radical‐initiated addition of the −PH 2 functions of optically pure L H , across the carbon−carbon double bonds of cycloalkenes C n H 2 n −2 ( n = 5−8), was employed as a method of preparation for the bis(secondary phosphanes) C 5 H 8 {P(H)R} 2 , where R = c C 5 H 9 , c C 6 H 11 , c C 7 H 13 , or c C 8 H 15 38a…”

“…Although the dialkylated bis(phosphanes) were formed without any notable diastereoselectivity and, hence, were isolated as more or less statistical mixtures of their ( R P , R P′ ), ( R P , S P′ ) [= ( S P , R P′ )], and ( S P , S P′ ) diastereomers, separation of these stereoisomers was feasible by further derivatization and subsequent metal complex formation 32,38. Thus, treatment of the isomeric mixtures with alkyllithium compounds, followed by alkylation with methyl iodide, caused the diastereomeric distributions to change in favor of the ( S , S )‐C 5 H 8 {( S )‐P(Me)C 8 H 15 c } 2 and ( R , R )‐C 5 H 8 {( R )‐P(Me)C 8 H 15 c } 2 stereoisomers,38a the rhodium( I ) complexes of which − [Rh{( S , S )‐C 5 H 8 [( R )‐P(Me)C 8 H 15 c ] 2 }(COD)]O 3 SCF 3 and [Rh{( R , R )‐C 5 H 8 [( S )‐P(Me)C 8 H 15 c ] 2 }(COD)]O 3 SCF 3 , respectively − were isolated as diastereomerically pure crystals by precipitation from a THF/diethyl ether solvent mixture 32,38b. Conversely, successive combination of the bis(secondary phosphane) isomers L H/ c Oc first with “triphosgene” (vide supra) and then with methylmagnesium bromide led to an enrichment of the ( S , S )‐C 5 H 8 {( R )‐P(Me)C 8 H 15 c } 2 and ( R , R )‐C 5 H 8 {( S )‐P(Me)C 8 H 15 c } 2 stereoisomers, which in turn were treated with [Rh(COD) 2 ]O 3 SCF 3 to furnish diastereomerically pure [Rh{( S , S )‐C 5 H 8 [( S )‐P(Me)C 8 H 15 c ] 2 }(COD)]O 3 SCF 3 and [Rh{( R , R )‐C 5 H 8 [( R )‐P(Me)C 8 H 15 c ] 2 }(COD)]O 3 SCF 3 , following chromatographic workup (Scheme 8) 32…”