Best Synthetic Methods: Enantioselective Oxidation and Reduction
Chemexpress Usually, only a single enantiomer of a pharmaceutical is the useful drug. Often, the synthesis of the single enantiomer depends on the ability to form C-O or C-N bonds with…
Functional Group Transformations
Jeffrey C. Pelletier of Wyeth Research, Collegeville, PA has developed (Tetrahedron Lett. 2007, 48, 7745. DOI: 10.1016/j.tetlet.2007.09.034)a easy work-up Mitsunobu procedure for the conversion of a primary alcohol such as…
Preparation of Heteroaromatic Derivatives
Several new routes to furans and to pyrroles have recently been put forward. Inspired by the Achmatowicz ring expansion, Patrick J. Walsh of the University of Pennsylvania developed (J. Am.…
Enantioselective Assembly of Aminated Stereogenic Centers
Although natural amino acids are readily available, there is a continuing need for unnatural amino acids. Jon C. Antilla of the University of South Florida has described (J. Am. Chem.…
Transition Metal-Mediated Construction of Carbocycles: Dimethyl Gloiosiphone A (Takahashi), Pasteurestin A (Mulzer), and Pentalenene (Fox)
There continue to be new developments in transition metal- and lanthanide-mediated construction of carbocycles. Although a great deal has been published on the asymmetric cyclopropanation of styrene, relatively little had…
Stereoselective C-N Ring Construction
Ryoichi Kuwano of Kyushu University showed (J. Am. 1-Hydroxyhept-6-yn-3-one structure Chem. Formula of 4-Bromo-3-fluoropicolinaldehyde Soc. 2008,130, 808. DOI: 10.1021/ja7102422)that diastereomerically and enantiomerically pure pyrrollidines such as 2 could be prepared…
Best Synthetic Methods: Oxidation and Reduction
Although methods both for reduction and for oxidation are well developed, there is always room for improvement. PMID:24059181 While ketones are usually reduced using metal hydrides, hydrogen gas is much…
New Methods for Carbon-Carbon Bond Construction
Mohammad Navid Soltani Rad of Shiraz University of Technology has shown (Tetrahedron Lett. 2007, 48, 6779.DOI: 10.1016/j.tetlet.2007.07.091)that with tosylimidazole (TsIm) activation in the presence of NaCN, primary, secondary and tertiary…
Palladium-Phosphinous Acid-Catalyzed Cross-Coupling of Acyl Chlorides
The group of Christian Wolf from Georgetown University, Washington, has reported on the synthesis of benzophenone and acetophenone derivatives via the Suzuki-type cross-coupling of aromatic and aliphatic acyl chlorides with…
Enantioselective Construction of Arrays of Stereogenic Centers
An impressive array of new catalysts for enantioselective homologation have been reported. Carlos F. Barbas III of Scripps/La Jolla has found (Angew. Chem. Int. Ed. 2007, 46, 5572. DOI: 10.1002/anie.200701269)that…