Chiral Media for Asymmetric Solvent Inductions. ( S,S )‐( + )‐1,4‐Bis(dimethylamino)‐2,3‐dimethoxybutane from ( R,R )‐( + )‐Diethyl Tartrate

Abstract

Chiral media for asymmetric solvent inductions. ( S,S )‐( + )‐1,4‐Bis(dimethylamino)‐2,3‐dimethoxybutane from ( R,R )‐( + )‐diethyl tartrate intermediate: (R,R)‐( + )‐N,N,N′,N′‐Tetramethyltartaric acid diamide reactant: 450 mL (7 mol) of liquid, anhydrous, cold (− 78°C) dimethylamine intermediate: (R,R)‐( + )‐2,3‐Dimethoxy‐N,N,N′,N′‐tetramethylsuccinic acid diamide product: (S,S)‐( + )‐1,4‐Bis (dimethylamino)‐2,3‐dimethoxybutane (DDB) reactant: (R,R)‐( + )‐diethyl tartrate reactant: (R,R)‐( + )‐tartaric acid (Firma Benckiser, D‐Ludwigshafen, or Firma Boehringer, D‐Ingelheim)

Bis(Pinacolato)Diboron

“…It is either taken from a cylinder (Aldrich Chemical Company, Inc.) or from a mixture of 50% aqueous solution of dimethylamine and potassium hydroxide. 5 5. Boron tribromide purchased from Wako Pure Chemical Industries, Ltd. is used without further purification.…”

Novel chiral ionic liquids: physicochemical properties and investigation of the internal rotameric behaviour in the neat system

“…Instrumental procedures NMR spectroscopy. 1 H and 13 C[ 1 H]NMR spectra were all recorded on a Bruker Advance DPX 300 or Bruker Ultrashieldt 400 plus spectrometer at 25 1C using deuterated dimethyl sulfoxide (dmso-d 6 ) or trichloromethane (CDCl 3 ) as a solvent. Variable temperature NMR experiments were recorded on a Bruker Advance DRX 500 spectrometer combined with a Eurotherm K B-VT 2000 temperature controller; solutions were prepared at 40 mM in dmso-d 6 .…”

“…All optical rotations a were measured on a Perkin-Elmer Model 341 digital polarimeter at 20 1C with concentration c = 1.0 (1.0 g per 100 cm 3 of CHCl 3 ). The specific optical rotation [a] 20 D (in units of 10 4 deg cm 3 dm À1 g À1 ) given by eqn (1), where l is the path length (1 dm) of plane polarised light (l = 589 nm, sodium-D line), was determined for all new chiral products:…”

“…Combination of chirality with ionic liquids still encourages the imagination of many scientists all over the world. Chiral ionic liquids as an alternative to chiral molecular solvents 1 possess undeniably crucial advantages: negligible volatility, higher level of order due to Coulombic interactions, and ease of separation and reusability. 2 Since the report of a room-temperature lactate-based chiral ionic liquid in 1999, 3 many examples of chiral cations and anions were created and explored for various applications.…”

A Life for Organic Synthesis – Dieter Seebach at 65

“…In fact, CAS indexes a full paper on the diastereoselective synthesis of nitroaldol derivatives [76] as a review article. Also beyond review status, the 14 contributions written for Organic Syntheses serve as a demonstration for the wide applicability and usefulness of the synthetic methodology developed in his group [77][78][79][80][81][82][83][84][85][86][87][88][89][90]. The group of compounds described herein reflects the large number of synthetic methods that over the years have made D. Seebach a household name for organic chemists both in academia and industry.…”