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Monday, September 10, 2012
Douglass F. Taber
University of Delaware

Reactions of Alkenes

Fung-E Hong of National Chung Hsing University devised (Adv. Synth. Catal. 2011, 353, 1491. DOI: 10.1002/adsc.201000899) a protocol for the oxidative cleavage of an alkene 1 (or an alkyne) to the carboxylic acid 2. Patrick H. Dussault of the University of Nebraska found (Synthesis 2011, 3475. DOI: 10.1055/s-0030-1260244) that Na triacetoxyborohydride reduced the methoxy hydroperoxide from the ozonolysis of 3 to the aldehyde 4. Reductive amination of 4 can be effected in the same pot with the same reagent.

Philippe Renaud of the University of Bern used (J. Am. Chem. Soc. 2011, 133, 5913. DOI: 10.1021/ja110224d) air to promote the free radical reduction to 6 of the intermediate from the hydroboration of 5. Robert H. Grubbs of Caltech showed (Org. Lett. 2011, 13, 6429. DOI: 10.1021/ol202790n) that the phosphonium tetrafluoroborate 8 prepared by hydrophosphonation of 7 could be used directly in a subsequent Wittig reaction.

Dominique Agustin of the Université de Toulouse epoxidized (Adv. Synth. Catal. 2011, 353, 2910. DOI: 10.1002/adsc.201100439) the alkene 9 to 10 without solvent other than the commercial aqueous t-butyl hydroperoxide. Justin M. Notestein of Northwestern University effected (J. Am. Chem. Soc. 2011, 133, 18684. DOI: 10.1021/ja204761e) cis dihydroxylation of 9 to 11 using 30% aqueous hydrogen peroxide.

Chi-Ming Che of the University of Hong Kong devised (Chem. Commun. 2011, 47, 10963. DOI: 10.1039/C1CC13574K) a protocol for the anti-Markownikov oxidation of an alkene 12 to the aldehyde 13. Aziridines such as 14 are readily prepared from alkenes. Jeremy B. Morgan of the University of North Carolina Wilmington uncovered (Org. Lett. 2011, 13, 5444. DOI: 10.1021/ol202410v) a catalyst that rearranged 14 to the protected amino alcohol 15.

A monosubstituted alkene 16 is particularly reactive both with free radicals and with coordinately unsaturated metal centers. An variety of transformations of monosubstituted alkenes have been reported. Nobuharu Iwasawa of the Tokyo Institute of Technology employed (J. Am. Chem. Soc. 2011, 133, 12980. DOI: 10.1021/ja205186k) a Pd pincer complex to catalyze the oxidative mono-borylation of 16 to give 17. The 1,1-bis boryl derivatives could also be prepared. Professor Renaud effected (J. Am. Chem. Soc. 2011, 133, 13890. DOI: 10.1021/ja2054989) radical addition to 16 leading to the terminal azide 18. Pei Nian Liu of the East China University of Science and Technology showed (Tetrahedron Lett. 2011, 52, 6113. DOI: 10.1016/j.tetlet.2011.09.025) that triflic acid on silica gel promoted the Markownikov amination of 16 to give 19.

Jean-Luc Vasse and Jan Szymoniak of the Université de Reims reported (Org. Lett. 2011, 13, 6292. DOI: 10.1021/ol202796w) a Zr-based protocol for the net hydroacylation of 16 with an acid chloride, leading to 20. Erik J. Alexanian of the University of North Carolina showed (J. Am. Chem. Soc. 2011, 133, 20146. DOI: 10.1021/ja2091883) that a secondary alkyl iodide could participate in Pd-mediated Heck coupling with 16 to give 21. Timothy F. Jamison of MIT observed (J. Am. Chem. Soc. 2011, 133, 19020. DOI: 10.1021/ja209235d) the complementary regioselectivity in the Ni-mediated addition of benzylic chlorides to 16, leading to 22. Professor Jamison also effected (Org. Lett. 2011, 13, 6414. DOI: 10.1021/ol2027015) the Ru-mediated addition of a silyl alkyne to 16, to give 23. Professor Renaud developed (Adv. Synth. Catal. 2011, 353, 3467. DOI: 10.1002/adsc.201100473) a free radical strategy for converting 16 to 24. Koji Yonehara of the Nippon Shokubai Co. carried (Adv. Synth. Catal. 2011, 353, 1071. DOI: 10.1002/adsc.201100006) 16 on to the α-methylene lactone 25, and Dmitry A. Astashko of Belarusian State University converted (Tetrahedron Lett. 2011, 52, 4792. DOI: 10.1016/j.tetlet.2011.07.042) 16 to the dihydropyrone 26.

D. F. Taber, Org. Chem. Highlights 2012, September 10.