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Monday, March 28, 2011
Douglass F. Taber
University of Delaware

Organic Functional Group Conversion

Pradeep Kumar of the National Chemical Laboratory, Pune, developed (Tetrahedron Lett. 2010, 51, 744. ) a new procedure for the conversion of an alcohol 1 to the inverted chloride 3. Michel Couturier of OmegaChem devised (J. Org. Chem. 2010, 75, 3401. ) a new reagent for the conversion of an alcohol 4 to the inverted fluoride 6. For both reagents, primary alcohols worked as well.

Patrick H. Toy of the University of Hong Kong showed (Synlett 2010, 1115. ) that diethylazodicarboxylate (DEAD) could be used catalytically in the Mitsunobu coupling of 7. Employment of 8 minimized competing acetate formation. In another application of hypervalent iodine chemistry, Jaume Vilarrasa of the Universitat de Barcelona observed (Tetrahedron Lett. 2010, 51, 1863. ) that the Dess-Martin reagent effected the smooth elimination of a pyridyl selenide 10.

Ken-ichi Fujita and Ryohei Yamaguchi of Kyoto University extended (Org. Lett. 2010, 12, 1336. ) the "borrowed hydrogen" approach to effect conversion of an alcohol 12 to the sulfonamide 13. Dan Yang, also of the University of Hong Kong, developed (Org. Lett. 2010, 12, 1068, not illustrated. ) a protocol for the conversion of an allylic alcohol to the allylically-rearranged sulfonamide. Shu-Li You of the Shanghai Institute of Organic Chemistry used (Org. Lett. 2010, 12, 800. ) an Ir catalyst to effect rearrangement of an allylic sulfinate 14 to the sulfone. Base-mediated conjugation then delivered 15.

K. Rama Rao of the Indian Institute of Chemical Technology, Hyderabad devised (Tetrahedron Lett. 2010, 51, 293. ) a La catalyst for the conversion of an iodoalkene 16 to the alkenyl sulfide 17. Alkenyl selenides could also be prepared. James M. Cook of the University of Wisconsin, Milwaukee described (Org. Lett. 2010, 12, 464, not illustrated. ) a procedure for coupling alkenyl iodides and bromides with N-H heterocycles and phenols. Hansjörg Streicher of the University of Sussex showed (Tetrahedron Lett. 2010, 51, 2717. ) that under free radical conditions, the carboxylic acid derivative 18 could be decarboxylated to the alkenyl iodide 19.

Bimal K. Banik of the University of Texas-Pan American found (Synth. Commun. 2010, 40, 1730. ) that water was an effective solvent for the microwave-mediated addition of a secondary amine 21 to a Michael acceptor 20. Parthasarathi Das of Dr. Reddy's Laboratories, Hyderabad established (Tetrahedron Lett. 2010, 51, 899. ) the microwave-mediated coupling of a carboxylic acid 23 with a dithiocarbamate 24 to give directly the amide 25.

There is a continuing need for methods that can be used to specifically couple two peptide chains. Xuechen Li, also of the University of Hong Kong, devised (Org. Lett. 2010, 12, 1724. ) the salicylaldehyde ester 26 for this purpose. Condensation with an N-terminal serine or threonine led to the coupled hemiaminal 28, that was deprotected to give the coupled peptide 29. Lei Liu of the University of Science of Technology, Hefei, reported (Tetrahedron Lett. 2010, 51, 1793. ) a related protocol, based on N-alkoxy disulfide intermediates.

D. F. Taber, Org. Chem. Highlights 2011, March 28.
URL: https://www.organic-chemistry.org/Highlights/2011/28March.shtm