229485-69-2

Upstream product

• 98-59-9 p-toluenesulfonyl chloride 
• 153645-26-2 N-Boc-L-tert-leucinol 
• 112245-13-3 (S)-tert-leucinol 
• 24424-99-5 di-tert-butyl dicarbonate 

Downstream Products

• 286454-86-2 (S)‐1‐(diphenylphosphino)‐3,3‐dimethylbutan‐2‐amine 
• 286454-85-1 (S)-[1-[(diphenylphosphino)methyl]-2,2-dimethylpropyl]carbamic acid 1,1-dimethylethyl ester 

Relevant academic research and scientific papers

Isoselective ring-opening polymerization and asymmetric kinetic resolution polymerization of: Rac -lactide catalyzed by bifunctional iminophosphorane-thiourea/urea catalysts

A series of iminophosphorane-thiourea/urea bifunctional catalysts was synthesized and utilized for the isoselective ring-opening polymerization of rac-lactide. The ROPs were promoted efficiently, affording the polylactides with controlled molecular weight, narrow molecular weight distribution and well-defined end groups without undesired side reactions. The experiment data revealed that ROPs of rac-LA are a "controlled/living" process. The highest stereoselectivity (Pm) was up to 0.80 using rac-IPU-1 under mild reaction conditions. The mechanistic study indicated that stereoselective ROPs of rac-LA were mainly controlled by a chain-end control mechanism when using rac/(R,R)-IPTU-1/IPU-1 as catalysts. Additionally, the ee values of -11% at 0 °C and -17% at -40 °C were achieved at about 50% conversion using (S)-IPU-2 as a chiral catalyst. The selectivity factor (s = kL/kD) of 1.6 indicated that a clear kinetic resolution occurred and the enantiomorphic site control mechanism was involved.

Synthesis and reactivities of enantiomerically pure β hydroxyalkyl and β-aminoalkyl ferrocenyl sulfides

Enantiomerically pure β-hydroxyalkyl and β-aminoalkyl ferrocenyl sulfides have been synthesized in good yields from mercaptoferrocene and amino alcohol derivatives. Primary β-aminoalkyl sulfides allowed the synthesis of tetrahydro-1,4-thiazepines containing the ferrocene moiety with good diastereoselectivity and β-iminoalkyl sulfides. Some of these derivatives have successfully been employed as ligands for palladium-catalyzed allylic substitution, with asymmetric induction of up to 99% ee. ( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).

Versatile chiral bidentate ligands derived from α-amino acids: Synthetic applications and mechanistic considerations in the palladium- mediated asymmetric allylic substitutions

A new class of chiral amidine-phosphine hybrid ligands 7a,b, which are readily accessible from the corresponding α-amino acids, were developed. A versatility for construction of new ligands is desirable, by which a variety of reactions and substrates become applicable. Indeed, a variety of modifications, such as exchange reactions to other amino groups in the amidine skeleton and the production of other types of ligands, are possible using the precursor compounds of 7a. Thus, novel chiral ligands 7c,d, 8, 11, and 13, which provide sterically and electronically different chiral circumstances, were prepared and used for the palladium-mediated asymmetric allylic substitutions of both acyclic and cyclic compounds. In these reactions, high levels of asymmetric induction were achieved for both substrates. A marked advancement of reactivity and enantioselectivity in palladium-catalyzed asymmetric allylations of 1,3-diphenylpropen-2-yl pivalate 14a was attained by examination of electronic substituent effects in a new series of chiral P-N and S-N hybrid ligands 8 and 11. Mechanistic views concerning the enantiodiscriminating step were demonstrated, in which a good correlation between a novel Pr/Mr concept and the absolute configuration of allylation products are discussed for the prediction of enantioselecting direction. The use of ketene silyl acetals as nucleophiles was investigated and compared with the corresponding harder anionic carbon nucleophiles. The former nucleophiles afforded higher enantioselectivity in asymmetric allylic transformations of 14a.

Novel diamino and diimino thioethers - Chiral tridentate ligands for asymmetric Michael reactions

Novel C2-symmetric enantiopure β,β'-diamino thioethers 1 and β,β'- diimino thioethers 2 have been prepared from chiral α-amino acids. Nine of these compounds have been screened as ligands, in combination with 13 metal salts, with a view to achi