New Methods for Functional Group Conversion

Yujiro Hayashi of Tokyo University of Science and Temaki Mukaiyama of the Kitasato Institute developed (Chem. Lett. 2008, 37, 592) a reduction-oxidation method for converting primary, secondary (such as 1, with clean inversion) and tertiary alcohols to sulfides. Peter A. Crooks of the University of Kentucky found Chem. Lett. 2008, 37, 528) that tet-rabenzylpyrophosphate 5 was an effective agent for condensing an acid 4 with an amine 6 to give the amide 7. This protocol, that runs in near quantitative yield in an hour at room temperature, with all impurities readily removable by washing with aqueous base and aqueous acid, appears to be well-suited both for scale-up, and for solid-phase synthesis. 

Balchandra M. Bhanage of the University of Mumbai reported Tetrahedron Lett. 2008, 49, 965) the reductive amination of aldehydes, including 8, and ketones to the corresponding amines, using and an inexpensive Fe catalyst. Andre Charette of the Universite de Montreal 

Matthew Tudge of Merck Rahway demonstrated Tetrahedron Lett. 2008, 49, 1041) that Br in DME activated NaBH, allowing facile reduction of esters, including the congested diester 14, at ambient temperature. David 1. Procter of the University of Manchester made J. Am. Chem. Soc. 2008,130,1136) the remarkable observation that six-membered 

It is well known that tertiary ally lie alcohols such as 21 can be oxidized to the corresponding enone 23 with chromium reagents. Yoshiharu Iwabuchi of Tohoku University observed (J. Org. Chem. 2008, 73, 4750) that the oxammonium salt 22 derived from TEMPO effected the same transformation. David E. Richardson of the University of Florida found (Tetrahedron Lett. 2008, 49, 1071) that could be used to oxidize N-methyhnorpholine in situ to the N-oxide, that in turn reoxidized catalytic OsO. In the presence of the Sharpless ligand, the dihydroxylation proceeded withhighee. This approach could offer cost and waste stream advantages over currently used oxidants. 

Sekar of the Indian Institute of Technology Madras, in Chennai, established (Tetrahedron Lett. 2008, 49, 2457) a convenient procedure for oxidizing primary alcohols such as 26 to the acid 27. Secondary alcohols were oxidized to ketones. AUyhc and benzylic alcohols could be oxidized in preference to saturated alcohols. Tobin J. Marks ofNorthwestem University devised (Organic Lett. 2008,10, 317) a La catalyst for the oxidative amination of aldehydes. In its present incarnation, excess aldehyde served as the reductant. If a less expensive reductant could be found, this would be a very useful procedure, avoiding the carboxyhc acid activation usually required for amide formation. 

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