Access to Optically Pure 4- and 5-Substituted Lactones: A Case of Chemical−Biocatalytical Cooperation
作者:Shaozhao Wang、Margaret M. Kayser、Valdas Jurkauskas
DOI:10.1021/jo026605q
日期:2003.8.1
pure or highly enantiomerically enriched 4- and 5-substituted lactones are rather difficult to obtain. Chemical or enzymaticsyntheses alone are not particularly successful. A combination of chemical catalysis and biocatalysis, however, provides a convenient route to a variety of these useful chiral compounds. In this paper we describe the synthesis of several optically pure 4- and 5-substituted lactones
Chiral ferrocene phosphane-carbenes are good ligands for the copper-catalyzed 1,4-addition of Grignard reagents to various Michael acceptors. The products were obtained in high enantiomeric purity (up to e.r. = 95:5) and excellent regioselectivity (r.r. = 99:1). These ligands are also useful for domino conjugate addition followed by enolate trapping with imine and aldehyde. (C) 2013 Elsevier B.V. All rights reserved.
YARUTA, GORO;MORI, KENJI, J. AGR. CHEM. SOC. JAP., 1982, 56, N 12, 1121-1125
作者:YARUTA, GORO、MORI, KENJI
DOI:——
日期:——
HIRATAKE, JUN;INAGAKI, MINORU;YAMAMOTO, YUKIO;ODA, JUNISHI, J. CHEM. SOC. PERKIN TRANS., 1,(1987) N 5, 1053-1058
<i>Lower Rim</i> Functionalized Chiral Resorc[4]arenes Derived from Citronellal and Carvone
作者:Jochen Mattay、Michael Schiendorfer
DOI:10.1055/s-2005-872108
日期:——
In our work we have provided the lower rim of resorc[4]arenes with stereogenic centers as well as with functional groups. For the synthesis of these lower rim functionalized chiral resorc[4]arenes we have used aldehydes derived from citronellal and carvone. In general, the functional group was introduced into the aldehyde compound prior to the final cyclization step. In the case of substitution of the functional group by chloride ions during the cyclization step under standard conditions (HCl-EtOH, Î), hydrochloric acid was replaced by the conjugated acid of the functional group. Another strategy is the introduction of the iodo group at the lower rim of a resorc[4]arene, which can be easily substituted by good nucleophiles and mild bases without protection of the upper rim.