Organic Chemistry Portal
Organic Chemistry Highlights

Monday, May 16, 2011
Douglass F. Taber
University of Delaware

Advances in Organic Functional Group Transformation

There have been several significant advances in N-alkylation using alcohols. Matthias Beller of Universitšt Rostock devised (Angew. Chem. Int. Ed. 2010, 49, 8126. DOI: 10.1002/anie.201002576) a Ru catalyst for the amination of secondary and benzylic primary alcohols with ammonia. Dieter Vogt of the Eindhoven University of Technology reported (Angew. Chem. Int. Ed. 2010, 49, 8130. DOI: 10.1002/anie.201002583) related transformations. Pei-Qiang Huang of Xiamen University showed (Chem. Commun. 2010, 46, 7834. DOI: 10.1039/C0CC01487G) that debenzylation of 3 in methanol led to the N-methyl amine 4. Parallel results have been reported with Ir (J. Am. Chem. Soc. 2010, 132, 15108. DOI: 10.1021/ja107274w), Au (Chem. Eur. J. 2010, 16, 13965. DOI: 10.1002/chem.201001848) and Cu (Chem. Lett. 2010, 39, 1182. DOI: 10.1246/cl.2010.1182).

Peter J. Scammells of Monash University found (J. Org. Chem. 2010, 75, 4806. DOI: 10.1021/jo1008492) that demethylation of an N-oxide could be effected with Fe powder. Yao Fu and Qingxiang Guo of the University of Science and Technology of China N-vinylated (Tet. Lett. 2010, 51, 5476. DOI: 10.1016/j.tetlet.2010.08.029) a sulfonamide 7 with vinyl acetate and a Pd catalyst. Acyl amides could also be N-vinylated under these conditions.

Hirokazu Urabe of the Tokyo Institute of Technology reported (Org. Lett. 2010, 12, 4137. DOI: 10.1021/ol101541p) that the stereodefined secondary sulfonamide of 9 could be displaced by an internal nucleophile, to give the product 11 with inversion of absolute configuration. Teruo Umemoto of IM&T Research devised (J. Am. Chem. Soc. 2010, 132, 18199. DOI: 10.1021/ja106343h) the remarkable fluorinating agent 13. In addition to converting secondary alcohols to the corresponding fluorides and ketones to gem-difluorides, 13 cleanly converted the carboxylic acids of 12 to trifluoromethyl groups.

Paul G. Williard of Brown University demonstrated (Org. Lett. 2010, 12, 5378. DOI: 10.1021/ol102029u) that LDA converted an allyl ether 15 specifically to the (Z)-propenyl ether 16. Phil Lee Ho of Kangwon National University and Sunggak Kim of Nanyang Technological University could add (Angew. Chem. Int. Ed. 2010, 49, 6806. DOI: 10.1002/anie.201001799) a phosphate to an alkyne 17 to make either the less substituted or the more substituted enol phosphate. Professor Kim reported (J. Org. Chem. 2010, 75, 7928. DOI: 10.1021/jo101543q) similar results with the addition of carboxylic acids.

Nigel Ribeiro of the Universitť de Strasbourg effected (Synlett 2010, 2928. DOI: 10.1055/s-0030-1259009) smooth elimination of the allylic thioether 19 to the triene 20. Itaru Nakamura of Tohoku University found (Org. Lett. 2010, 12, 4198. DOI: 10.1021/ol1017504) that a hydrazone 21 could be rearranged to the nitrile 22.

Samuel J. Danishefsky of Sloan-Kettering devised (J. Am. Chem. Soc. 2010, 132, 17045. DOI: 10.1021/ja1084628) conditions for coupling the glycopeptides 23 and 24. Remarkably, the assembly of 25 was successful even with unprotected hydroxyl groups on the sugars and on the peptide.

D. F. Taber, Org. Chem. Highlights 2011, May 16.