Fatima, Daissa, Belaidi SalahTouhami, Lanez2023-11-212023-11-212023-09Fatima Daissa 1 , Salah Belaidi 1*1*, Touhami Lanez 21,*1.CONFORMATIONAL ANALYSIS AND STEREOCHEMICAL CONTROL IN MACROLIDES BY MOLECULAR MECHANICS AND BOLTZMANN DISTRIBUTIONI. Journal of Fundamental and sciences. vol.15, no 3. sebtembr2023. Faculty of exact sciences. university of el oued. [visited in 08/06/2023 available from [copy the link here]https://dspace.univ-eloued.dz/handle/123456789/30378artecalThe Conformational analysis and stereochemical control of 20 Membered Macrolides were investigated using molecular mechanics calculations, PM3 semi empirical method, and Boltzmann distribution. The results indicate that these macrocycles have a high degree of conformational flexibility. However, in the presence of tricarbonyliron, the number of favorable conformations was reduced to only four. The study also revealed significant diastereoselectivity (73:27) in B type complexed macrolides. Furthermore, it wa s observed that the methyl group in position α 2 had a local conformational effect that increased the diastereoselectivity of alkylation reactions. The high diastereoselectivity observed was attributed to the combination of stereochemical remote control wit h Fe(CO) 3 and local control by the methyl groupenMacrolide, Molecular me chanics, PM 3 , Boltzmann distribution, StereoselectivityArticle