54497-38-0

Upstream product

• 16052-42-9 (1R,2S,5R)-menthyl chloride 
• 591-51-5 phenyllithium 
• 75992-49-3 (-)-P-Chlordimenthylphosphin 
• 1610883-70-9 (R_P)-O-(-)-menthyl phenylphosphine oxide 
• 63474-24-8 (1R,2S,5R)-(-)menthylmagnesium chloride 
• 583-53-9 2,3-dibromobenzene 

Relevant academic research and scientific papers

Dimenthylphosphine P-Oxide as a Synthetic Platform for Bulky and Chiral Ligands with Dimenthylphosphino Donor Groups

Attaching di(1R)-menthylphosphino fragments (menthyl = Men = 1R,2S,5R-2-isopropyl-5-methylcyclohex-1-yl) to molecular scaffolds turns them into homochiral, bulky, electron-rich phosphine ligands with proven and potential applications in coordination chemistry and transition-metal catalysis. Dimenthylphosphine P-oxide (Men2POH; 1) is established as a platform chemical toward dimenthylphosphino-containing targets via transformation to the known ligand precursors dimenthylchlorophosphine (4) and dimenthylphosphine (6). Transformations of 1 to dimenthylphosphinyl chloride (5) and dimenthylphosphinic acid (8) are elaborated. A phospha-Michael type 1,4-addition of 1 to p-benzo-or 1,4-naphthoquinone gives the corresponding o-hydroxyaryl(dimenthyl)phosphine oxides. Deprotonation of 1 with n-BuLi provides a phosphinyl nucleophile, whose reactions with alkyl halides or 1,n-dihaloalkanes provide tertiary alkyl dimenthylphosphine oxides or 1,n-bis(dimenthylphosphino)alkane bis(P-oxides) 10a-c, respectively. As an example, oxide 10b was deoxygenated to the diphosphine Men2P(CH2)3PMen2 (11) and characterized via the square-planar complex [(Men2P(CH2)3PMen2)PdCl2] (12). A selection of P-aryl dimenthylphosphines, including PhP(Men)2 (19) and 2-ClC6H4P(Men)2 (22), as well as the menthyl analogues Men-JohnPhos (21) and Men-SPhos (24), of the respective Buchwald ligands have been prepared. The combination of the secondary phosphine oxide (SPO) 1 with PdCl2 produces halide-bridged [(Men2POH)2Pd2Cl2] (25), mononuclear [(Men2POH)2PdCl2] (26), or the halide-bridged pseudochelate complex [(Men2PO···H···OPMen2)2Pd2Cl2] (27), depending on the reaction stoichiometry and conditions, all of which have been crystallographically characterized. The new ligands 1, 19, 21, 22, and 24 and complexes 25 and 26 have been evaluated in model palladium-catalyzed C-C-and C-N-fragment coupling reactions and found to display specific reactivity profiles due to the presence of the menthyl groups. Ligand 22 in particular catalyzed an asymmetric biaryl-forming coupling to give 2-methoxy-1,1′-binaphthalene with an er of up to 93:7.

Nucleophilic substitution of p-stereogenic chlorophosphines: Mechanism, stereochemistry, and stereoselective conversions of diastereomeric secondary phosphine oxides to tertiary phosphines

A diastereomeric mixture of secondary phosphine oxide is stereospecifically converted to chlorophosphine salt by treatment with oxalyl chloride, which stereoselectively affords P-inverted or retained tertiary phosphines, depending on the substitution with aliphatic or aromatic Grignard reagents, respectively, in high to 99% yield and 99:1 dr. The repulsion of π- electron on aryl to lone electron pair on phosphorus is proposed for the P-retained substitution.

Enantioselective catalysis 113: New menthylphosphane ligands differing in steric and electronic properties

A concept for bisphosphane ligands was developed, in which chirality is derived from the optically active (1R,3R,4S)-menthyl substituents in PMen2 groups and the backbone between the phosphorus units is varied (o-phenylene, 2,2'-biphenylene, 1,1'-ferrocenediyl); one of the two PMen2 groups was also replaced by a PPh2 unit. The synthesis and characterisation of seven new menthylphosphanes is described. Emphasis is put on the NMR assignment of the menthyl protons by two-dimensional methods and 13C-1H shift correlation. The ligands have been used in Rh and Ni complexes in several model reactions of enantiosclective catalysis giving optical inductions in the low to middle range.