Syntheses and crystal structures of the cinchona alkaloid derivatives used as ligands in the osmium-catalyzed asymmetric dihydroxylation of olefins
摘要:
Experimental procedures for the preparation of two classes of derivatives of the cinchona alkaloids dihydroquinine and dihydroquinidine are described. Ligands (DHQ)2-PHAL, la, and (DHQD)2-PHAL, 2a, are conveniently synthesized in good yield by the reaction of the corresponding alkaloid with 1,4-dichlorophthalazine in the presence of K2CO3 and KOH in refluxing toluene. Derivatives DHQ-PHN, lb, and DHQD-PHN, 2b, are prepared through an Ullmann-type coupling between the 9-0-alkaloid sodium alkoxide and 9-iodophenanthrene in the presence of CuI and pyridine. Crystal structures for derivatives 2a and 2b are also presented. These four alkaloid derivatives serve as highly enantioselective ligands for the osmium tetraoxide catalyzed asymmetric dihydroxylation (AD) of olefins.
A ligand structure-enantioselectivity relationship for the osmium-catalyzed asymmetric dihydroxylation of olefins
作者:Yasukazu Ogino、Hou Chen、Eric Manoury、Tomoyuki Shibata、Matthias Beller、Doris Lübben、K. Barry Sharpless
DOI:10.1016/s0040-4039(00)93549-4
日期:1991.10
highest enantioselectivities to date for various olefins are obtained in the osmium-catalyzed asymmetricdihydroxylation using new 9-O-aromatic dihydroquinidine and dihydroquinine ligands. A ligand structure-enantioselectivity relationship (LSER) is developed, and representative results for quinine-based ligands are reported for the first time.
Organocatalytic Asymmetric Cyanosilylation of Nitroalkenes
作者:Pablo Bernal、Rosario Fernández、José M. Lassaletta
DOI:10.1002/chem.201001107
日期:——
New catalyst, new reaction: The unprecedented cyanosilylation of nitroalkenes can be efficiently catalyzed by a bifunctional quinine derivative with tetraalkylammonium cyanide and thiourea moieties. The activation of the nitroalkene by hydrogen bonding to the thiourea, together with the presence of an “active” cyanide, provides a new mode of activation that leads to products in high yields and good
[EN] PROCESS FOR PREPARING DIASTEREOMERICALLY ENRICHED PHOSPHORAMIDATE DERIVATIVES OF NUCLEOSIDE COMPOUNDS FOR TREATMENT OF VIRAL INFECTIONS<br/>[FR] PROCÉDÉ DE PRÉPARATION DE DÉRIVÉS DE PHOSPHORAMIDATES ENRICHIS EN DIASTÉRÉO-ISOMÈRES DE COMPOSÉS DE NUCLÉOSIDES, DESTINÉS AU TRAITEMENT D'INFECTIONS VIRALES
申请人:BRISTOL MYERS SQUIBB CO
公开号:WO2014008236A1
公开(公告)日:2014-01-09
The present invention is directed to a process for preparing diastereomerically enriched nucleoside phosphoramidates having the formula I:
[EN] STEREOSELECTIVE MANUFACTURE OF SELECTED PURINE PHOSPHORAMIDATES<br/>[FR] PRODUCTION STÉRÉOSÉLECTIVE DE PHOSPHORAMIDATES DE PURINE SÉLECTIONNÉS
申请人:ATEA PHARMACEUTICALS INC
公开号:WO2022040473A1
公开(公告)日:2022-02-24
The present invention provides stereoselective processes of manufacture for the phosphoramidate nucleotide Compound 1 or a pharmaceutically acceptable salt thereof.