Modeling the Effect of Substitution on the Pb(OAc)4 Mediated Oxidative Cleavage of Steroidal 1,2-Diols

• Published in: Journal of organic chemistry Vol. 70; no. 18; pp. 7080 - 7086
• Main Authors: Öztürk, C, Topal, K, Aviyente, V, Tüzün, Nurcan Ş, Sánchez Fernández, E, Arseniyadis, S
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 02.09.2005; Amer Chemical Soc
• Subjects: Alicyclic compounds, terpenoids, prostaglandins, steroids; Chemistry; Chemistry, Organic; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with o, s, se, te hetero atom and condensed derivatives; Organic chemistry; Physical Sciences; Preparations and properties; Science & Technology; Steroids; ELEMENTS; MOLECULAR CALCULATIONS; PATTERN; EFFECTIVE CORE POTENTIALS; HETERO-DOMINO TRANSFORMATIONS; DERIVATIVES; SOLVENT; Substituent effect; Steroid; Diol; Electrophilic addition; Lead Acetate; Oxygen heterocycle; Modeling; Density functional method; Cleavage; Oxidation; Ethylenic compound; Lead complex; Successive reaction
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo0505627

We comment on the effects of angular substitution on the outcome of a Pb(OAc)4 (LTA) mediated heterodomino reaction, with selected bicyclic unsaturated 1,2-diols, which is considered to proceed through a series of transformations in a single vessel. The first two, oxidative and pericyclic, are followed by the key step, an electrophilic addition of LTA to the olefin, responsible for the course of the domino process. In this study, the electrophilic addition of LTA to the double bond has been modeled with B3LYP, where the 6-31G* basis set is used for C, O, and H atoms and the LANL2DZ method is used for Pb. The modeling in the gaseous phase and in solution has revealed the concerted nature of the addition of LTA to the double bond of the intermediate. The fact that LTA adds from the same side as the substituent R, for RH and from the opposite side when RCH3 has been attributed to steric hindrance, which causes deformation of the olefinic intermediate.