75992-49-3

Upstream product

• 63474-24-8 (1R,2S,5R)-(-)menthylmagnesium chloride 
• 16052-42-9 (1R,2S,5R)-menthyl chloride 

Downstream Products

• 105892-80-6 dimenthyl(trimethylsilyl)phosphine 
• 54497-38-0 (-)-dimenthylphenylphosphine 
• 235422-42-1 [(R)-menthyl]2PCH₂SnMe₃ 
• 192325-03-4 [(R)-menthyl]2PCH₂SnPh₃ 

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.

Stereochemistry of the Menthyl Grignard Reagent: Generation, Composition, Dynamics, and Reactions with Electrophiles

Menthyl Grignard reagent 1 from either menthyl chloride (2) or neomenthyl chloride (3) consists of menthylmagnesium chloride (1a), neomenthylmagnesium chloride (1b), trans-p-menthane (4), 2-menthene (8), 3-menthene (9), and Wurtz coupling products including symmetrical bimenthyl 13. The diastereomeric ratio 1a/1b was determined in situ by 13C NMR or after D2O quenching by 2H NMR analysis. Hydrolysis of the C-Mg bond proceeds with retention of configuration at C-1. The kinetic ratio 1a/1b from Grignard reagent generation (dr 59:41 at 50 °C in THF) is close to the thermodynamic ratio (56:44 at 50 °C in THF). Carboxylation of 1 at -78 °C separates diastereomers 1a/b to give the anion of menthanecarboxylic acid (19) from 1a, which combines with unreactive 1b to give neomenthylmagnesium menthanecarboxylate (1bI). The kinetics of epimerization for the menthyl/neomenthylmagnesium system was analyzed (ΔH? = 98.5 kJ/mol, ΔS? = -113 J/mol·K for 1bI → 1aI). Reactions of 1 with phosphorus electrophiles proceed stereoconvergently at C-1 of 1a/b to give predominantly menthyl-configured substitution products: PCl3 and 2 equiv of 1 give Men2PCl (6), which hydrolyzes to dimenthylphosphine P-oxide (7), whereas Ph2PCl with 1 equiv of 1 gave P-menthyldiphenylphosphine oxide (27) after workup in air.

Menthyl-Substituted Phosphorus Compounds, II. L-Men(R)P(X)Cl (R = Cl, L-Me, D-Men; X = :, S). Characterization of Singular, Diastereotopic and Enantiotopic Menthyl Groups by 1H, 13C and 31P NMR Techniques

Menthyl-substituted phosphorus compounds L-Men(R)P(X)Cl (R = Cl, L-Men, D-Men; X = :, S) are synthesized. 1D and 2D NMR studies on nuclei 1H, 13C and 31P were used to characterize singular, diastereotopic and enantiotopic menthylgroups. - Key words: Menth