Some uses of tin compounds in organic synthesis.
University of Cambridge
Department of Chemistry
Doctor of Philosophy (PhD)
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Rowley, M. (1986). Some uses of tin compounds in organic synthesis. (Doctoral thesis). https://doi.org/10.17863/CAM.11490
The work described in the dissertation is concerned mainly with organo-tin chemistry. In the first part, I describe the investigation of the stereochemistry of intramolecular electrophilic attack on a tin-carbon bond. The react ion of a number of cS - and � -s tanny 1 a lcoho 1 s and 0-stannyl acid chlorides was investigated, but stereochemical information was obtained only with the reaction of a 0-stannyl aldehyde to give a cyclopentanol, which proceeded largely with retention of configuration at the tin-bearing carbon, unlike the reaction of cS -stannyl alcohols, which give cyclopropanes with inversion. The second piece of work is a regio- and stereo-specific synthesis of allyl stannanes. s-stannyl ester enolates were treated with aldehydes to give alcol products with fairly good stereoselectivity: (~) and (~) enolates gave major products with different aldol relative stereochemistry. These aldols could be converted to s - hydroxy acids, then treatment with d imethy 1 formamide dimethyl acetal gave allyl stannanes stereospecifically, where steric and reactivity effects allowed. Thirdly, an investigation of the reaction of a tin cuprate with allenes is described. The cuprate reacts with 1,1-dimethyl allene followed by aqueous work up to give an allyl stannane, or the intermediate copper species can be quenched with a number of different ele,ctrophiles to give further substituted allyl stannanes. Similarly, allene itself reacts to give either vinyl or allyl stannanes, depending on the conditions used. Unfortunately, the factors governing the regiochemistry of the reaction with allene are not yet fully understood, and mixtu r es of products often result. Finally, I describe efforts to perform a kinetic resolution of a racemic Grignard reagent in which the chiral centre is the meta 1-bear ing carbon. It was hoped that react ion of the Gr ignard with half an equivalent of an optically active carbonyl compound would leave the remaining Gr ignard partially reso 1 ved. However, this did not prove to be successful.
This record's DOI: https://doi.org/10.17863/CAM.11490