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Monday, February 25, 2013
Douglass F. Taber
University of Delaware

Arrays of Stereogenic Centers: The Carbery Synthesis of Mycestericin G

Chi-Ming Che of the University of Hong Kong devised (Chem. Comun. 2011, 47, 11204. ) a manganese catalyst for the enantioselective cis-dihydroxylation of electron-deficient alkenes such as 1. Christine Greck of Université de Versailles-St-Quentin effected (Tetrahedron Lett. 2012, 53, 1085. ) enantioselective alkoxylation of 3, remarkably without β-elimination. Keiji Maruoka of Kyoto University developed (J. Am. Chem. Soc. 2012, 134, 7516. ) an organocatalyst for the enantioselective anti addition of 5 to 6, to give 7. Barry M. Trost of Stanford University developed (J. Am. Chem. Soc. 2012, 134, 2075. ) a Mg catalyst for the enantioselective addition of ethyl diazoacetate to an aldehyde 8, and carried the adduct on to 9.

Professor Maruoka designed (Angew. Chem. Int. Ed. 2012, 51, 1187. ) for the enantioselective addition of a ketone 10 to the alkynyl ketone 11, to give 12. Naoya Kumagai and Masakatsu Shibasaki of the Institute of Microbial Chemistry found (Org. Lett. 2012, 14, 3108. ) that 14 could be added under very soft conditions to 13 to give the anti adduct 15. René Peters of the Universität Stuttgart added (Adv. Synth. Catal. 2012, 354, 1443. ) the azlactone formed in situ to 17 in a conjugate sense to give 18. Kaïss Aouadi and Jean-Pierre Praly of the Université de Lyon prepared (Tetrahedron Lett. 2012, 53, 2817. ) the nitrone 19 from the inexpensive (-)-menthone. Dipolar cycloaddition to a range of alkenes proceeded with substantial diastereocontrol, as illustrated for 20, which gave the crystalline adduct 21.

Jeffrey S. Johnson of the University of North Carolina reduced (J. Am. Chem. Soc. 2012, 134, 7329. ) the α-keto ester 22 under equilibrating conditions to give the lactone 23. Claudio Palomo of the Universidad del País Vasco alkylated (J. Org. Chem. 2012, 77, 747. ) the aldehyde 24 with 25 to give the diester 26. Damien Bonne and Jean Rodriguez of Aix-Marseille Université added (Adv. Synth. Catal. 2012, 354, 563. ) the α-keto ester 27 to 28 in a conjugate sense to give 29. Glenn C. Micalizio of Scripps/Florida developed (Angew. Chem. Int. Ed. 2012, 51, 5152. ) for the stereocontrolled construction of skipped-conjugate dienes such as 30. Hydroxyl-directed hydrogenation then delivered 31 as a single dominant diastereomer.

David R. Carbery of the University of Bath optimized (Org. Lett. 2012, 14, 756. ) the diastereoselective Claisen rearrangement of 32 to give the benzyl ester 33. This was carried on via cross metathesis to the immunosuppressant Mycestericin G (34).

D. F. Taber, Org. Chem. Highlights 2013, February 25.
URL: http://www.organic-chemistry.org/Highlights/2013/25February.shtm