Chiral N-Heterocyclic Carbenes
Chemexpress N-heterocyclic salts are air-stable crystalline solids that can be stored with no special precautions and are the precursors of N-Heterocyclic Carbenes (NHCs), which are produced upon treatment with an appropriate…
Transition Metal Mediated Carbocyclic Construction
Alkene and alkyne metathesis have, in a relatively short time, become important tools for organic synthesis. Carlos Saá of the Universidad de Santiago de Compostela has developed (J. Am. PMID:23927631…
Catalytic Enantioselective Construction of Alkylated Stereogenic Centers
One of the simplest ways to construct alkylated ternary centers is enantioselective catalytic hydrogenation. Xumu Zhang of Pennsylvania State University has devised (Angew. Chem. Int. Ed. 2005, 44, 4933. 1803603-34-0…
Stereoselective Construction of Nitrogen Heterocycles
Nitrogen heterocycles are the basis of many essential pharmaceuticals, and of many physiologically-active natural products. There is a continuing interest in the development of new methods for the construction of…
Functional Group Transformation
Two particularly useful conversions of alcohols were recently reported. PMID:23381601 Buy2,4,5-Trichloroquinoline Abdol Reza Hajipour of the University of Wisconsin has found (Tetrahedron Lett. 2006, 47, 4191.DOI: 10.1016/j.tetlet.2006.04.036)that grinding an alcohol…
Catalytic Enantioselective Aldol/Mannich Reactions Leading to Extended Arrays of Stereogenic Centers
There are several strategies now available for the catalytic construction of isolated oxygenated and aminated stereogenic centers in high enantiomeric excess (2006 Jan 9). Processes for the catalytic enantioselective construction…
Preparation of Heteroaromatics
Thomas J. J. Müller of the Universität Heidelberg has reported (Chem. Methyltrioxorhenium(VII) structure 5-(Thiazol-5-yl)nicotinic acid web Commun. 2005, 2581.DOI: 10.1039/b502324f)a powerful method for the assembly of highly substituted furans, Pd-mediated…
Organocatalytic Preparation of Enantiomerically-Pure Carbocycles
Enantiomerically-pure carbocycles can be prepared either de novo, or by desymmetrization of prochiral rings. A classic illustration of the latter approach is the condensation of cyclohexanone (1) with p-nitrobenzaldehyde (2).…
Best Synthetic Methods
The Strecker synthesis is the one-carbon homologation of an aldehyde to the α-amino nitrile. Robert Cunico of Northern Illinois University in DeKalb reports (Tetrahedron Lett. 2003, 44, 8025.DOI: 10.1016/j.tetlet.2003.09.006)a modified…
Stereocontrolled Construction of O-Heterocycles
Homoallylic secondary alcohols such as 1 are readily prepared in enantiomerically-pure form by enantioselective addition of allyl anions to the aldehyde. Subhas Chandra Roy of the Indian Association for the…