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.