Menthylsubstituierte Phosphorverbindungen, II. L-Men(R)P(X)Cl (R = Cl, L-Men, D-Men; X = :, S). Charakterisierung singulärer, diastereotoper und enantiotoper Menthylgruppen durch ¹H-, ¹³C- und ³¹P-NMR-Techniken/ Menthyl-Substituted Phosphorus Compounds, II L-M en(R)P(X)Cl (R = Cl, L-Men, D-Men; X =:, S). Characterization of Singular, Diastereotopic and Enantiotopic Menthyl-Groups by ¹H, ¹³C and ³¹P NMR Techniques

Abstract

<jats:title>Abstract</jats:title><jats:p>Menthyl-substituted phosphorus compounds L-M en(R )P(X )Cl(R = Cl, L-M en, D -Men ; X = :, S) are synthesized. ID and 2 D NMR studies on nuclei <jats:sup>1</jats:sup>H , <jats:sup>13</jats:sup>C and <jats:sup>31</jats:sup>P were used to characterize singular, diastereotopic and enantiotopic menthylgroups.</jats:p>

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

“…Combination of 1 with PCl 3 in a 2:1 ratio followed by heating to reflux is the standard procedure to prepare Men 2 PCl ( 6 ) . The reported yield is low at 13% or 25–35% . Analysis of the reaction mixture is considerably simplified by quenching with D 2 O ( 1 → (3-D 1 )- 4 ) and hydrolysis of 6 to phosphine oxide 7 (Scheme ).…”

“…Menthyl Grignard reagent 1 is prepared in the usual way from menthyl chloride ( 2 ) and magnesium in etheric solution. , This chiral organometallic reagent is widely used to attach menthyl groups to electrophilic centers. Reactions have been described, e.g., with carbon dioxide, − formaldehyde, dichloromethane, PCl 3 , ,, PhPCl 2 , Ph 2 PCl, ,, GeCl 4 , SnCl 4 , or organotin chlorides. ,, The reagent has also been used in cross-coupling , or transmetalation reactions . The products tend to retain menthyl configuration, and the sequence from 2 via 1 to various substitution products ( Men - E ) has usually been assumed to proceed with retention of configuration in all steps (Scheme ).…”

“…The present work emerged from an analysis of synthetic routes to P , P -dimenthylphosphane-based chiral phosphorus ligands. , We have previously reported on the nucleophilic chlorination of menthol ( 5 ) to menthyl chloride ( 2 ) and accompanying rearrangements . In continuation of those studies, we wished to investigate the synthesis of Men 2 PCl ( 6 ) from 1 and PCl 3 , which is low-yielding (13%, 25–35%) and suffers from the difficult separation of the water- and oxygen-sensitive 6 from byproducts. We anticipated that hydrolytic workup would convert 6 to dimenthylphosphine P -oxide ( 7 ), whose expected stability toward water and air might facilitate its isolation (Scheme ).…”

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

“…The menthyl group (Men, or {1 R ,2 S ,5 R }-2-isopropyl-5-methylcyclohex-1-yl, if attached to atoms heavier than carbon) is a structural element often applied to the synthesis of chiral phosphine ligands. − The dimenthylphosphino (Men 2 P−) fragment − ,, may be considered a congener of established P , P -dialkylphosphino donor centers with σ-donating alkyl groups ( tert -butyl, cyclohexyl, or 1-adamantyl) that can be classified as dispersion energy donors (DED) . Such groups have been recognized as key elements in the rational design of ligands for transition-metal-catalyzed fragment-coupling reactions, hydrogenation (as e.g.…”

Rearrangement in Stereoretentive Syntheses of Menthyl Chloride from Menthol: Insight into Competing Reaction Pathways through Component Quantification Analysis

“…Among those, most common reagents are menthyl chloride ( 2 ; Scheme a, b), neomenthyl chloride ( 4 ), or various menthyl sulfonates . Even though the sulfonates are easier to prepare, menthyl chloride retains particular importance as starting material for the Grignard reagent menthylmagnesium chloride ( 5 ) that permits attachment of menthyl groups to electrophilic centers, such as in reactions with carbon dioxide, PCl 3 ,[7b], , Ph 2 PCl, GeCl 4 , SnCl 4 , or organotin chlorides . In addition, the reagent finds use in cross‐coupling, or transmetalation reactions , .…”