Asymmetric aminohydroxylation of substituted styrenes: applications in the synthesis of enantiomerically enriched arylglycinols and a diamine
作者:Peter O’Brien、Simon A. Osborne、Daniel D. Parker
DOI:10.1039/a803821j
日期:——
The catalytic asymmetric aminohydroxylation of a variety of styrene derivatives and vinyl aromatics using osmium tetroxide in conjunction with alkaloid-derived ligands [e.g. (DHQ)2PHAL or (DHQD)2PHAL] and haloamine salts of alkyl carbamates (e.g. ethyl carbamate or tert-butyl carbamate) has been investigated. By observing the effect of different aromatic substituents and alkyl carbamates on the regioselectivity, yield and enantioselectivity of the aminohydroxylation reactions, a number of conclusions have been reached: (i) the 1-aryl-2-hydroxyethylamine regioisomers were obtained as the major products in reasonable yield and high (87%) enantiomeric excess; (ii) tert-butyl carbamate was superior to ethyl carbamate in terms of yield, enantioselectivity and ease of removal of the N-protecting group; (iii) high (96%) enantioselectivity was observed with a 4-methoxy-substituted styrene whereas ortho-substituted styrenes gave lower enantioselectivities; (iv) chiral ligands (DHQ)2PHAL and (DHQD)2PHAL gave essentially equal and opposite senses and degrees of asymmetric induction; (v) regioselectivity was ligand dependent with better regioselectivity (and therefore higher isolated yields) obtained with (DHQ)2PHAL than with (DHQD)2PHAL. The products of the aminohydroxylation reactions were used to prepare enantiomerically enriched arylglycinols and a chiral diamine.
Asymmetric aminohydroxylation of substituted styrenes using t-butyl carbamate
作者:Peter O'Brien、Simon A. Osborne、Daniel D. Parker
DOI:10.1016/s0040-4039(98)00665-0
日期:1998.6
A variety of substituted styrenes have been aminohydroxylated using t-butyl carbamate to give either enantiomer of highly enantiomerically enriched N-Boc protected amino alcohols in good yields. Better levels of regioselectivity were observed with (DHQ)(2)PHAL than with (DHQD)(2)PHAL even though the enantioselectivities observed were comparable. One of the amino alcohol products was converted into a novel chiral diamine. (C) 1998 Elsevier Science Ltd. All rights reserved.
INHIBITORS OF Akt ACTIVITY
申请人:SmithKline Beecham Corporation
公开号:EP1968568A2
公开(公告)日:2008-09-17
[EN] INHIBITORS OF Akt ACTIVITY<br/>[FR] INHIBITEURS D'ACTIVITE Akt
申请人:SMITHKLINE BEECHAM CORP
公开号:WO2007076423A2
公开(公告)日:2007-07-05
[EN] Invented are novel thiophene compounds, the use of such compounds as inhibitors of protein kinase B activity and in the treatment of cancer and arthritis. [FR] La présente invention concerne des composés de thiophène atypiques, l'utilisation de tels composés comme inhibiteurs de l'activité de la protéine kinase B et pour le traitement du cancer et de l'arthrite.
[EN] NOVEL HETEROARYL DERIVATIVE<br/>[FR] NOUVEAU DÉRIVÉ HÉTÉROARYLE