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. 2009 Nov 5;11(21):4774-6.
doi: 10.1021/ol901963v.

A synthesis of the carbon skeleton of maoecrystal V

Paul J Krawczuk  1 , Niklas Schöne, Phil S Baran
Affiliations

A synthesis of the carbon skeleton of maoecrystal V

Paul J Krawczuk et al. Org Lett. .

Abstract

An enantioselective synthesis of the maoecrystal V (1) carbon skeleton is described. The key transformations include arylation of a 1,3-dicarbonyl compound with a triarylbismuth(V) dichloride species, oxidative dearomatization of a phenol, and a subsequent intramolecular Diels-Alder reaction.

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Figures

Figure 1
Figure 1
Representations of maoecrystal V.
Scheme 1
Scheme 1
Maoecrystal V: (A) Retrosynthetic Analysis, (B) Model Study, and (C) Synthesis of the Complete Carbon Skeletona aDetails: reagents and conditions (a) CAN, NaHCO3, MeOH, 0°C, 46% , (b) Li(t-BuO)3AlH, THF, −78°C, 53%, (c) acryloyl chloride, Et3N, DMAP, DCM, 0°C, 36%, (d) TBSOTf, Et3N, DCM, 63%, (e) Pd/C, O2, PhMe, 110°C, 99%, (f) Pb(OAc)4, AcOH, 59%, (g) 165°C, o-DCB, ca. 60%, (h) Ar3BiCl2(13), DBU, PhMe, 67%, (i) Li(t-BuO)3AlH, THF, −78°C, 72%, (j) acryloyl chloride, DIEPA, DMAP, DCM, −78°C, 69%, (k) TFA, DCM, 0°C, 65%, (l) Pb(OAc)4, AcOH, 81%, dr = 3:7, (m) 165°C, o-DCB, BHT 79% for 20, 69% for 21 (n) BF3•OEt2, DCM, 82%, (o) H2, Pd/C, EtOAc, 97% for 23, 99% for 24 (p) SmI2, MeOH, THF, 0°C, 76%, dr = 17:3. CAN = cerium ammonium nitrate, DMAP = 4-dimethylaminopyridine, DCM = dichloromethane, TBSOTf = tert-butydimethylsilyl trifluoromethylsulfonate, o-DCB = ortho-dichlorobenzene, DIEPA = diisopropylethylamine, DBU = 1,8-diazobicylco[5.4.0]undec-7-ene, TFA = trifluoroacetic acid, BHT = 2,6-di-tert-butyl-p-cresol.
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References

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