@article{comins_joseph_hong_alawar_foti_zhang_chen_lamunyon_guerraweltzien_1997, title={Asymmetric synthesis and synthetic utility of 2,3-dihydro-4-pyridones}, volume={69}, ISSN={["0033-4545"]}, DOI={10.1351/pac199769030477}, abstractNote={Abstract}, number={3}, journal={PURE AND APPLIED CHEMISTRY}, author={Comins, DL and Joseph, SP and Hong, H and Alawar, RS and Foti, CJ and Zhang, YM and Chen, XH and LaMunyon, DH and GuerraWeltzien, M}, year={1997}, month={Mar}, pages={477–481} }
 @article{comins_lamunyon_chen_1997, title={Enantiopure N-acyldihydropyridones as synthetic intermediates: Asymmetric syntheses of indolizidine alkaloids (-)-205A, (-)-207A, and (-)-235B}, volume={62}, ISSN={["0022-3263"]}, DOI={10.1021/jo971448u}, abstractNote={Concise asymmetric syntheses of indolizidine alkaloids (-)-205A, (-)-207A, and (-)-235B were accomplished with a high degree of stereocontrol in eleven steps. Addition of 4-(1-butenyl)magnesium bromide to 1-acylpyridinium salt 5, prepared in situ from 4-methoxy-3-(triisopropylsilyl)pyridine and the chloroformate of (+)-trans-2-(alpha-cumyl)cyclohexanol, gave a 91% yield of diastereomerically pure dihydropyridone 6. Oxidative cleavage of 6 and subsequent reduction provided alcohol 7 in 81% yield. Removal of the chiral auxilliary and TIPS group (NaOMe; 10% HCl), N-acylation with BnOCOCCl, and treatment with NCS/Ph(3)P gave chloride 10. Methylation at C-3, copper-mediated conjugate addition of 4-(benzyloxy)butylmagnesium bromide, and vinyl triflate formation provided 13 in a stereoselective fashion. Catalytic reduction of the vinyl triflate moiety, simultaneous cleavage of the benzyl ether and Cbz groups, and cyclization to give amino alcohol 14 was effected via a one-pot reaction. Oxidation of 14 with the Dess-Martin reagent gave a 97% yield of amino aldehyde 4. Synthesis of each of the three title alkaloids was accomplished in one step from 4. The Seyferth-Gilbert reaction provided a 41% yield of (-)-205A. The appropriate Wittig olefination of 4 gave indolizidines (-)-207A and (-)-235B in 70% and 86% yield, respectively.}, number={23}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Comins, DL and LaMunyon, DH and Chen, XH}, year={1997}, month={Nov}, pages={8182–8187} }