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Enantioselective Total Synthesis of (+)-Gliocladin C and (+)-Gliocladine C 石枫 2011-7-9 Larry E. Overman, Org. Lett., 2007, 9, 339 Larry E. Overman, J.

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Presentation on theme: "Enantioselective Total Synthesis of (+)-Gliocladin C and (+)-Gliocladine C 石枫 2011-7-9 Larry E. Overman, Org. Lett., 2007, 9, 339 Larry E. Overman, J."— Presentation transcript:

1 Enantioselective Total Synthesis of (+)-Gliocladin C and (+)-Gliocladine C 石枫 2011-7-9 Larry E. Overman, Org. Lett., 2007, 9, 339 Larry E. Overman, J. Am. Chem. Soc. 2011,133, 6549

2 (+)-Gliocladine C They were isolated from fungal secondary metabolites. They showed a wide range of bioactivities. (+)-Gliocladin C

3 Enantioselective Total Synthesis of (+)-Gliocladin C Larry E. Overman, Org. Lett., 2007, 9, 339

4 Sythesis of starting material from isatine: J. Am. Chem. Soc. 1958, 80, 2257 Muthusamy, S. J. Chem. Soc., Chem. Commun. 2002, 824 Overman, L. E. Org. Lett. 2005, 7, 2795

5 TBDMS: t-butyl dimethyl silyl DTBMP: 2,6-di-tert-butyl-4-methylpyridine (to prevent desilylation of the siloxy nucleophile) Mukaiyama aldol reaction CSA: 樟脑磺酸 Rychnovsky’s method

6 TBDMSCl: TBAF: BOP: benzotriazole-1-yloxy- tris(dimethylamino)phosphonium hexafluorophosphate

7 Mulliez, M.; Royer, J. Tetrahedron 1984, 40, 5143 Mulliez’s method From isatine to (+)-Gliocladin C: 21 steps, ~4% overall yield. next

8 Mukaiyama aldol reaction: Pioneer work: Mukaiyama, T., Chem. Lett. 1973, 1011; Mukaiyama, T., J. Am. Chem. Soc. 1974, 96, 7503 Mechanism: back

9 Mechanism: back

10 Rychnovsky’s method: Scott D. Rychnovsky, J. Am. Chem. Soc. 1994,116,1753 Mechanism: back

11 The action of BOP: The action of TMSI: back

12 (+)-Gliocladin C Enantioselective Total Synthesis of (+)-Gliocladine C Larry E. Overman, J. Am. Chem. Soc. 2011,133, 6549

13 Steglich-type rearrangement

14 PPTS: pyridinium p-toluenesulfonateDess Martin periodinane (DMP): Soai reduction Soai reduction: LiBH 4 -MeOH (Esters, lactones, and epoxides) Soai, K.; Ookawa, A. J. Org. Chem. 1986, 51, 4000

15

16 majorminor OsO 4 /NMO1:120:1 AD-Mix-  14:120:1 AD-Mix-  5:120:1 NMO: N- 甲基吗啉氧化物 Sharpless asymmetric dihydroxylation

17 From isatine to (+)-Gliocladin C: 10 steps, 11% overall yield. From precursor of (+)-Gliocladin C to (+)-Gliocladine C: 6 steps, 29% yield. Org. Lett., 2007, 9, 5267.

18 Mechanism of acid-promoted ionic reduction: Mechanism of ring-closing: back

19 Steglich-type rearrangement: Pioneer work: Steglich, W. Tetrahedron Lett. 1970, 11, 4727 Black, T. H. J. Chem. Soc. Chem. Commun. 1986, 1524

20 Catalytic enantioselective Steglich-type rearrangement : Fu, G. C. Angew. Chem., Int. Ed. 2003, 42, 3921 Vedejs, E. J. Am. Chem. Soc. 2003, 125, 4166 Vedejs, E. J. Am. Chem. Soc. 2003, 125, 13368;

21 Mechanism of Steglich-type rearrangement: back

22 Sharpless asymmetric dihydroxylation (SAD): Sharpless, K. B. J. Am. Chem. Soc. 1980, 102, 4263 Sharpless, K. B. J. Am. Chem. Soc. 1988, 110, 1968 Empirical model: (DHQ) 2 PHAL (DHQD) 2 PHAL AD-mix  : (DHQ) 2 PHAL+K 2 OsO 2 (OH) 4 +K 3 Fe(CN) 6 AD-mix  : (DHQD) 2 PHAL+K 2 OsO 2 (OH) 4 +K 3 Fe(CN) 6

23 Mechanism of SAD :

24 Synthetic applications of SAD : Armstrong, A. J. Org. Chem. 2000, 65,7020 Burke, S. D. Org. Lett. 1999, 1, 71. back

25 Mechanism of sulfur substitution: back


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