ABSTRACT
(S)-tert-Butylsulfinylferrocene was submitted to ortho-metalation, and the corresponding lithium derivative was trapped by alkyl or aryl imines bearing various electron-withdrawing groups on the nitrogen atom (Ts, Dpp, Boc). New aminosulfoxides were obtained with complete diastereocontrol when Dpp or Boc groups were used. The absolute configuration (SS,SFc,S) has been determined by single-crystal X-ray analysis and chemical correlation. An unusual pseudocyclic boatlike transition state has been proposed to explain the stereochemical course of this reaction.
Subject(s)
Ferrous Compounds/chemical synthesis , Imines/chemistry , Lithium/chemistry , Crystallography, X-Ray , Ferrous Compounds/chemistry , Models, Molecular , Molecular Conformation , StereoisomerismABSTRACT
Enantiopure aromatic (phenyl, naphthyl) and heteroaromatic (pyridyl, quinolyl, diazinyl) sulfoxides have been synthesized by reaction of (S)-tert-butyl tert-butanethiosulfinate with aryl- or heteroaryllithium derivatives. The ortho-directed metalation of the sulfoxides was performed with lithium bases. Subsequent addition of the lithiated intermediates to N-tosylimines afforded tosylaminoalkyl tert-butylsulfinyl arenes. In most cases a complete asymmetric induction was highlighted in favor of (S,S) isomers. Heating the aminosulfoxides provided an original cyclization to form novel cyclic sulfenamides. A novel enantiopure synthesis of a benzylamine was described. An application of an enantiopure aminosulfoxide as N,S ligand for the asymmetric catalysis of allylic nucleophilic substitution has been successfully tested.
Subject(s)
Benzylamines/chemical synthesis , Hydrocarbons, Aromatic/chemistry , Imines/chemistry , Metals/chemistry , Organometallic Compounds/chemical synthesis , Sulfoxides/chemical synthesis , Benzylamines/chemistry , Catalysis , Ligands , Molecular Conformation , Organometallic Compounds/chemistry , Stereoisomerism , Sulfoxides/chemistryABSTRACT
The 3-chloropyridazine moiety was immobilized on a Wang resin, using two different methodologies. The first of these involved direct nucleophilic substitution of 3,6-dichloropyridazine with the alcoholate of Wang resin. The experimental conditions were optimized. The second method involved a Mitsunobu reaction between the Wang resin and 6-chloropyridazin-3-ol during which a problem of regioselectivity was observed. The so-obtained chloropyridazine-containing resins were subsequently reacted with various arylboronic acids under Suzuki conditions. Acid cleavage yielded 6-arylpyridazin-3(2H)-ones with high chemical purity.
Subject(s)
Chemistry, Pharmaceutical , Combinatorial Chemistry Techniques , Hydrazones/chemical synthesis , Hydrocarbons, Aromatic/chemistry , Pyridazines/chemical synthesis , Boronic Acids/chemistry , Cross-Linking Reagents , Models, Chemical , Resins, Synthetic/chemistryABSTRACT
[reaction: see text] Regioselective metalation of pyrazines and cross-coupling reactions provides an easy access to botryllazines A and B and to an isomer of botryllazine A with good yields from chloropyrazine.
