144192-69-8

Upstream product

• 108-98-5 thiophenol 
• 146351-72-6 [(1,1-dimethylethyl)(dimethyl)silyloxy]acetic acid methyl ester 
• 18162-48-6 tert-butyldimethylsilyl chloride 

Downstream Products

• 181294-27-9 (2S,3S)-3-Benzoylamino-2-hydroxy-3-phenyl-thiopropionic acid S-phenyl ester 
• 186596-02-1 (4S,5R)-2,4-Diphenyl-4,5-dihydro-oxazole-5-carbothioic acid S-phenyl ester 

Relevant academic research and scientific papers

Taxol semisynthesis: A highly enantio- and diastereoselective synthesis of the side chain and a new method for ester formation at C-13 using thioesters

A very simple, new, and straightforward approach to the Paclitaxel (Taxol) and Docetaxel (Taxotere) side chains has been developed using the imine addition reaction of thioester-derived boron enolates bearing chiral ligands. The addition reaction was studied extensively, using a combination of different thioesters (ROCH2COSPh, ROCH2COSt-Bu), oxygen protecting groups (R = Bn, TBDMS, COPh, EE, TMS), chiral boron ligands [derived from both (-) and (+)-menthone], imines (PhCH=NSiMe3, PhCH=NCOPh), and in the presence or in the absence of additional Lewis acids (BF3-OEt2, Et2AlCl, TiCl4). The side chain was assembled in a few steps with the correct relative (syn) and absolute stereochemistry (2R,3S). The stereochemical outcome of the boron-mediated reaction was rationalized using chair vs boat transition state structures. A new direct route for attachment of the side chains to the baccatin nucleus using thioester chemistry has also been developed. By treatment of a mixture of a thioester (8, 12, or 17) and protected baccatin III (2b, 2c) with LHMDS, the 13-0 acylated compounds were obtained in high yield (up to 90%). Hydrolysis of 18b gave Paclitaxel (1a) in 80% yield.

Highly enantio- and diastereoselective boron aldol reactions of α-heterosubstituted thioacetates with aldehydes and silyl imines

Boron enolates derived from α-heterosubstituted thioacetates and bearing menthone-derived chiral ligands react with aldehydes to give anti aldols with excellent diastero- and enantiocontrol. Boron enolates derived from tert-butyl α-halothioacetate and bearing menthone-derived chiral ligands react with imines with excellent diastero- and enantiocontrol to give syn α-halo-β-aminothioesters, which can be converted to the corresponding aziridines by simple ring closure during LAH reduction. A key precursor of antibiotics (+)-thiamphenicol and (-)-florfenicol was synthesized.

Semisynthese von Taxol: eine hochenantio- und -diastereoselektive Synthese der Seitenkette und eine neue Methode zur Esterbildung an C13 unter Verwendung von Thioestern

Keywords: Asymmetrische Synthesen; Enolate; Imine; Taxol; Thioester