CONFORMATIONAL EFFECTS IN COMPOUNDS WITH 6‐MEMBERED RINGS. X. SYNTHESIS OF CIS‐ AND TRANS‐3,5‐DI‐TERT‐BUTYLTHIANE AND SULFONIUM SALT FORMATION FROM THIANES
作者： P. J. HALFPENNY , P. J. JOHNSON , M. J. T. ROBINSON , M. G. WARD
关键词: Cis–trans isomerism 、 Steric effects 、 Medicinal chemistry 、 Methyl iodide 、 Reactivity (chemistry) 、 Stereochemistry 、 Chemistry 、 Stereospecificity 、 Conformational isomerism 、 Sulfonium 、 Chromic acid
摘要: Abstract Convenient stereospecific syntheses of cis- and trans-3,5-di-t-butylthian (1 2) have been developed. The reaction between anancomeric thians with unhindered S atoms methyl iodide has investigated a range kinetic (from 6.5 up to 11:1) thermodynamic 1.25 2.8:1) stereoselectivities, equatorial + -Me always favoured, observed. It is concluded that the observed stereoselectivities are best explained by steric hindrance at axial site on sulphur twist conformers do not contribute significantly reactivity most in such reactions. contrast relative shown either N-methylpiperidines or different directions approach these 6-membered rings during attack. Acid anhydrides isolated from oxidation β-diketones ozone chromic acid.
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