Best Synthetic Methods: Reduction
Chemexpress Aryl amines are common constituents of pharmaceuticals, so there has been a great deal of interest in their preparation, e.g by Pd- or Cu-mediated amination of aryl halides. Multi-step procedures…
New Catalysts and Strategies for Alkene Metathesis
Alkene metathesis (“Grubbs Reaction”) is now well-developed as a synthetic method. Still, there is a continuing effort to develop more efficient catalysts, and to extend the range of substrates that…
Best Synthetic Methods: Functional Group Transformation
Selective halogenation can be a direct route to high value added materials from inexpensive hydrocarbons. José Barluenga of the Universidad de Oviedo has developed (Angew. Chem. Int. Ed. PMID:23514335 2005,…
Enantioselective Carbocyclic Construction
Richard P. Hsung, now of the University of Wisconsin, has reported (Org. Lett. 2006, 8, 231. Formula of 2-Hexyloctanoic acid Methyl 6-chloro-5-formylpicolinate site DOI: 10.1021/ol052487s)the intramolecular addition of ynamides to…
Catalytic Enantioselective Homologation of Aldehydes to Alcohols and Amines
Convergent coupling of a nucleophile with an aldehyde ideally will proceed with high enantioselectivity, while at the same time allowing the attachment of a usefully functionalized fragment. Several recently-reported aldehyde…
Enantioselective Construction of Naturally-Occurring Cyclic Ethers
Powerful methods for the stereocontrolled construction of cyclic ethers have recently been developed, enabling the synthesis of a variety of complex natural products. Many of the Annonaceous acetogenins, represented by…
Preparation of Heteroaromatic Derivatives
Heteroaromatics, including pyridines and indoles, play a prominent role in pharmaceutical chemistry. A new method for pyridine construction has recently been developed (Chem. Commun. 2006, 1313. DOI: 10.1039/b515901f) by Alexander…
Catalytic Enantioselective Construction of Alkylated Stereogenic Centers
There are several strategies now available for the catalytic enantioselective construction of oxygenated and aminated stereogenic centers. Catalytic processes for the enantioselective construction of alkylated stereogenic centers are just starting…
Enantioselective Ring Construction: Part One of Two
As new drug entities must be usually be prepared as single enantiomers, and as many contain one or more heterocyclic orcarbocyclic rings, there is an increased emphasis on the development…
Tandem Claisen-Mislow-Evans Rearrangement
Matthew J. Formula of 6-Bromo-2-oxaspiroheptane Pelc and Armen Zakarian from Florida State University have reported on the synthesis of A,G-spiroimine (1) of pinnatoxins (Tetrahedron Lett. 2006, 47, 7519. Sodium difluoromethanesulfinate…