Enantioselective Construction of Arrays of Stereogenic Centers: The Breit Synthesis of (+)-Bourgeanic Acid

Abstract

Kyungsoo Oh of Indiana University Purdue University Indianapolis devised (Organic Lett. 2009, 11, 5682) a new ligand that with Cu delivered predominantly one diastereomer of the Henry adduct 3, and with Zn delivered the other. Liu-Zhu Gong of the University of Science and Technology of China reported (Angew. Chem. Int. Ed. 2009, 48, 6503) the Darzens condensation of the diazoacetamide 5 with a variety of aldehydes to give the corresponding epoxy amides with high diastereo- and enantiocontrol. Michael J. Krische of the University of Texas, Austin, applied (Organic Lett. 2009, 11, 3108, 3112) his asymmetric allylation to a variety of primary diols including 7, leading to the homologated product 9. M. Christina White of the University of Illinois showed (J. Am. Chem Soc. 2009, 131, 11707) that Pd-mediated oxidative amination of carbamate 10 delivered the protected 1,3-amino alcohol 11 with high diastereocontrol. James P. Morken of Boston College devised (J. Am. Chem Soc. 2009, 131, 9134) a Pt catalyst for the asymmetric bis-boration of dienes. The allyl borane prepared from 12 added with high stereocontrol to benzaldehyde, to give, after oxidation, the diol 13. Carlos F. Barba III of Scripps/La Jolla optimized (Angew. Chem. Int. Ed. 2009, 48, 9848) an organocatalyst for the enantioselective conjugate addition of an alkoxy aldehyde 15 to a nitroalkene. Do Hyun Ryu of Sungkyunkwan University found (Chem. Commun. 2009, 5460) that an organocatalyst could also mediate the dipolar cycloaddition of a diazo ester 18 to an unsaturated aldehyde, giving 19 with high diastereo- and enantiocontrol. Francesco Fini and Luca Bernardi of the University of Bologna developed (J. Am. Chem Soc. 2009, 131, 9614) an organocatalyst that effected enantioselective dipolar cycloaddition of the nitrone derived from 20 to the unsaturated ester 21. Kevin Burgess of Texas A&M optimized (J. Am. Chem Soc. 2009, 131, 13236) an Ir catalyst for the enantioselective hydrogenation of trisubstituted alkenes such as 23. In the course of a synthesis of (+)-faranal, Varinder K. Aggarwal of the University of Bristol described (Angew. Chem. Int. Ed. 2009, 48, 6317) a one-pot procedure for the conversion of the allyl borane 25 into 27.