111612-93-2Relevant articles and documents
Applications of Zr-catalyzed carbomagnesation and Mo-catalyzed macrocyclic ring closing metathesis in asymmetric synthesis, enantioselective total synthesis of Sch 38516 (fluvirucin B1)
Xu, Zhongmin,Johannes, Charles W.,Houri, Ahmad F.,La, Daniel S.,Cogan, Derek A.,Hofilena, Gloria E.,Hoveyda, Amir H.
, p. 10302 - 10316 (2007/10/03)
The first enantioselective total synthesis of antifungal agent Sch 38516, also known as fluvirucin B1, is described. The synthesis includes a convergent asymmetric preparation of amine 17 and acid 18, which are then united to afford diene 62. Metal-catalyzed transformations play a crucial role in the synthesis of the latter moiety. Of particular note are the diastereo- and enantioselective Zr-catalyzed alkylations, a tandem Ti- and Ni-catalyzed process that constitutes a hydrovinylation reaction, and a Ru-catalyzed alcohol oxidation to afford carboxylic acid 18. The requisite carbohydrate 38 is synthesized in a highly diastereo- and enantioselective fashion. Optical purity of the carbohydrate moiety arises from the use of the asymmetric dihydroxylation method of Sharpless; diastereochemical control is achieved through a selective dipolar [3 + 2] cycloaddition with a readily available amine serving as the chiral auxiliary. Union of the appropriately outfitted carbohydrate 71 and diene 62 through an efficient and diastereoselective glycosylation is followed by a remarkably efficient Mo-catalyzed macrocyclization that proceeds readily at room temperature.
THE CHEMISTRY OF SILYLATED KETENE ACETALS: AN EFFICIENT STEREOCONTROLLED SYNTHESIS OF N-BENZOYL L-DAUNOSAMINE
Kita, Yasuyuki,Itoh, Fumio,Tamura, Osamu,Ke, Ya Yuan,Tamura, Yasumitsu
, p. 1431 - 1434 (2007/10/02)
N-Benzoyl L-daunosamine was synthesized with high stereoselectivity utilizing a 1,3-addition of ketene silyl acetal (3a) to the chiral nitrone, (Z)-((4R)-trans-2,2,5-trimethyl-1,3-dioxolan-4-yl)methylene((1S)-1-phenylethyl)amine N-oxide (4c) accompanied by a silyl group-transfer in acetonitrile under mild conditions.