Current Organic Chemistry, Volume 9, No. 14, 2005
Contents
Six-Membered Ring Spiranes: Carbocycles and Heterocycles
with Oxygen Pp.1287-1314
C.
Cismas, A. Terec, S. Mager and I. Grosu
Recent Advances in Catalytic Asymmetric Addition to
Imines and Related C=N Systems Pp.1315-1392
Tirayut
Vilaivan, Worawan Bhanthumnavin and Yongsak Sritana-Anant
The Structure, Biological Activities and Synthesis of
3- Hydroxylpyrrolizidine Alkaloids and Related Compounds Pp.1393-1418
Stephen
G. Pyne and Minyan Tang
Chemistry and Biology of Anti-Inflammatory Marine
Natural Products. Phospholipase A2 Inhibitors Pp.1419-1427
Luigi
Gomez-Paloma, Maria Chiara Monti, Stefania Terracciano, Agostino Casapullo and
Raffaele Riccio
Abstracts
[Back to top] Six-Membered Ring Spiranes: Carbocycles and
Heterocycles with Oxygen
C. Cismas, A. Terec, S. Mager and I. Grosu
The data concerning the structure, synthesis and reactivity of six-membered ring spiranes exhibiting carbocycles and heterocycles with oxygen atoms are reviewed. The structural aspects are discussed using specific stereogenic elements and stereochemistry descriptors for spiranes with six-membered rings. The data are supported by high field NMR investigations and molecular structures obtained by X-ray diffractometry. The general procedures and access to spiranes with carbocycles and with heterocycles with oxygen are commented.
[Back to top] Recent Advances in Catalytic Asymmetric Addition to
Imines and Related C=N Systems
Tirayut
Vilaivan, Worawan Bhanthumnavin and Yongsak Sritana-Anant
Addition reactions to imines are relatively less developed compared to those of carbonyl compounds due to low electrophilicity and ease of a-deprotonation. With the use of an appropriate activator, which can coordinate to the imine nitrogen atom, the electrophilicity of the imine can be enhanced and a range of nucleophilic addition reactions becomes possible. When the activator is chiral, it will also create chiral environment and will direct the approach of the nucleophile to one face of the imine over the other resulting in enantioselectivity. The potential of catalytic asymmetric addition to imines in organic synthesis is enormous, but is relatively underused. With the development of many highly effective chiral catalysts for imine additions, the situation will soon be changed. The present review will cover selected literature on catalytic asymmetric additions to aldimines, ketimines and related compounds including hydrazones, oximes and nitrones from 1999 to 2004. The reactions of interest include hydrogenation, alkylation, Mannich and related reactions such as aza-Baylis-Hillman and aza-Henry reaction, Strecker reaction, hydrophosphonylation, and 3-6 membered ring forming reactions from imines. Some applications of these methodologies in synthesis of nitrogen-containing biologically active compounds will also be presented.
[Back to top] The Structure, Biological Activities and Synthesis of 3-
Hydroxylpyrrolizidine Alkaloids and Related Compounds
Stephen
G. Pyne and Minyan Tang
This review reports on recent developments on the structure, biological activities and synthesis of 3-hydroxylpyrrolizidine alkaloids and related compounds.
[Back to top] Chemistry and Biology of Anti-Inflammatory Marine Natural
Products. Phospholipase A2 Inhibitors
Luigi
Gomez-Paloma, Maria Chiara Monti, Stefania Terracciano, Agostino Casapullo and
Raffaele Riccio
The chemical and biological properties of anti-inflammatory marine natural products whose mechanism of action involves inhibition of phospholipase A2 (PLA2), an enzyme of key importance in the biosynthesis of pro-inflammatory chemical signals and mediators, has been reviewed. Remarkably, most marine natural products display a selective inhibition profile against secretory PLA2 enzymes, with little or null ability to interfere with cytosolic PLA2. Variabilin, a marine furano-terpene, appears to be a notable exception, endowed with a distinctive dual inhibitor profile towards both secretory and cytosolic PLA2 proteins.