Construction of Single Stereocenters
James L. Leighton at Columbia University reported (Nature 2012, 487, 86. ) that the commercially available allylsilane 2 allylated acetoacetone (1) to furnish the enantioenriched tertiary carbinol 3. Alexander T. Radosevich demonstrated (Angew. Chem. Int. Ed. 2012, 51, 10605. ) that diazaphospholidine 5 induced the formal reductive insertion of 3,5-dinitrobenzoic acid to α-ketoester 4 to generate adduct 6 enantioselectively. Tehshik P. Yoon at the University of Wisconsin at Madison found (J. Am. Chem. Soc. 2012, 134, 12370. ) that aminoalcohol derivative 9 could be prepared via an asymmetric iron-catalyzed oxyamination of diene 7 using oxaziridine 8. A procedure for the desymmetrization of 1,3-difluoropropanol 10 by nucleophilic displacement of an unactivated aliphatic fluoride to generate 11 was reported (Angew. Chem. Int. Ed. 2012, 51, 12275. ) by Günter Haufe at the University of Münster and Norio Shibata at the Nagoya Institute of Technology.
An innovative procedure for the amination of unactivated olefins involving an ene reaction/[2,3]-rearrangement sequence (e.g. 12 to 13) was developed (J. Am. Chem. Soc. 2012, 134, 18495. ) by Uttam K. Tambar at the University of Texas Southwestern Medical Center. James P. Morken at Boston College demonstrated the stereospecific amination of borane 14 with methoxylamine to produce 15.
The conversion of β-ketoester 16 to 18 by amination with 17 under oxidative conditions was reported (J. Am. Chem. Soc. 2012, 134, 18948. ) by Javier Read de Alaniz at the University of California at Santa Barbara. The electrophilic amination of silyl ketene acetal 19 with a functionalized hydroxylamine reagent to produce 20 was disclosed (Angew. Chem. Int. Ed. 2012, 51, 11827. ) by Koji Hirano and Masahiro Miura at Osaka University.
Erick M. Carreira at the ETH Zürich developed (Angew. Chem. Int. Ed. 2012, 51, 8652. ) the enantioconvergent thioetherification of alcohol 21 to produce 23 with high branched to linear selectivity and ee. The asymmetric conjugate addition of 2-aminothiophenol 25 to 24 catalyzed by mesitylcopper in the presence of ligand 26 was developed (Angew. Chem. Int. Ed. 2012, 51, 8551. ) by Naoya Kumagai and Masakatsu Shibasaki at the Institute of Microbial Chemistry in Tokyo.
The enantioselective conversion of aldehyde 28 to α-fluoride 30 under catalysis by NHC 29 was developed (Angew. Chem. Int. Ed. 2012, 51, 10359. ) by Zhenyang Lin and Jianwei Sun at the Hong Kong University of Science and Technology. The team of Spencer D. Dreher at Merck Rahway and Patrick J. Walsh at the University of Pennsylvania reported (Angew. Chem. Int. Ed. 2012, 51, 11510. ) cross-coupling at the benzylic position of amine 31 to generate 32 with high ee.
Tomonori Misaki and Takashi Sugimura at the University of Hyogo reported (Chem. Lett. 2012, 41, 1675. ) that guanidine 34 catalyzed the addition of oxazolone 33 to alkynone 35 to produce 36 in high ee. Finally, we developed (J. Am. Chem. Soc. 2012, 134, 5552. ) cyclopropenimine 38 as a highly effective new Brĝnsted base catalyst, which effected the enantioselective addition of glycine imine 37 to methyl acrylate to produce 39 rapidly, on scale, and with high ee.