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Monday, April 18, 2011
Douglass F. Taber
University of Delaware

C-O Ring Construction: (-)-Sclerophytin A (Morken), (+)-Dictyosphaeric Acid (Taylor), Goniothalesdiol A (Xie/She), (-)-7-Deoxyloganin (Lupton), (-)-Apicularen A (Uenishi)L-783, 277 (Banwell)

In the course of a synthesis of (-)-Sclerophytin A (3), James P. Morken of Boston College showed (J. Am. Chem. Soc. 2010, 132, 16380. DOI: 10.1021/ja108185z) that Oshima-Utimoto conditions transformed 1 into 2 with high stereo- and regiocontrol.

En route to (+)-Dictyosphaeric Acid (6), Richard J. K. Taylor of the University of York found (Angew. Chem. Int. Ed. 2010, 49, 5574. DOI: 10.1002/anie.201002416) that the intramolecular Michael cyclization of 4 proceeded smooothly to give 5.

Xingang Xie and Xuegong She of Lanzhou University devised (Synlett 2010, 2283. DOI: 10.1055/s-0030-1258016) the In-mediated cyclization of 7 with benzaldehyde, to effect an elegant synthesis of Goniothalesdiol A (9).

The carbene-mediated cyclization of 10 to 11 developed (Org. Lett. 2010, 12, 4836. DOI: 10.1021/ol101983h) by David W. Lupton of Monash University set the stage for the synthesis of (-)-7-Deoxyloganin (12).

Jun'ichi Uenishi of Kyoto Pharmaceutical University showed (Org. Lett. 2010, 12, 4160. DOI: 10.1021/ol101753y) that the Pd-mediated cyclization of 13 proceeded with high diastereocontrol. Intramolecular esterification than led to (-)-Apicularen A (15).

Martin G. Banwell of the Australian National University established (Heterocycles 2010, 82, 313. DOI: 10.3987/COM-10-S(E)67) that LiHMDS was effective for the cyclization of the alkynyl Weinreb amide 16 to 17. Reduction and deprotection completed the synthesis of the resorcylic lactone L-783, 277 (18).

D. F. Taber, Org. Chem. Highlights 2011, April 18.