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A study on the organic chemistry of tin and tin hydride radical chemistry reports on the results of the synthesis and analysis of eight members of a new family of highly fluorinated tin hydrides as reagents for radical reactions. It provides some of the first detailed information on how the nature and composition of fluorous chains affects the reactivity and solubility of fluorous reagents. Experimental methodology and results are presented.

A series of (2-pyridyl)indoles was synthesized from the palladium(0)-mediated reaction of (1-(tert-nutyldimethylsilyl)-3- indolyl)zinc chloride and (1-(benzenesulfonyl)-2-indolyl)zinc chloride. The resulting products were utilized for the synthesis of the indolo[2,3-alpha]quinolizidine system via the stereoselective hydrogenation of thge pyridine ring followed by electrophilic cyclization in the indole 3-position.

The cyclization of pure all-cis 3-(2-piperidyl)indole was carried out to examine epimerization reactions at the C-2 and C-4 positions of the piperidine ring. Specifically, the piperidine-4-carboxylic acids obtained from the saponification of the 3-(2-piperidyl)indoles were reesterified with excess diazomethane. The results revealed that epimerization occurs at the C-2 position of the piperidine during alkaline hydrolysis of the ester.

The use of supercritical CO2 as a reaction solvent has been limited, and a solution could be to use radical reactions that proceed well in nonpolar solvents. The simple reduction of bromoadamantane to adamantane, conducting radical reactions by initial pressurization to 850 psig, was investigaed. Tris(perfluorohexylethyl)tin hydride was soluble under reaction conditions, although a mixture with tributyltin hydride was not homogenous.

The preparation and characterization of tris 2-(perfluorohexyl)ethyl tin hydride as a fluorous agent in combinatorial synthesis using organic substrates is discussed. The tin hydride was obtained from 2-perfluorohexyl-1-iodoethane via a series of steps culminating in reduction with lithium aluminum hydride in ether. To enable its efficient implementation, a homogeneous reaction medium, a benzotrifluoride otherwise known as (trifluoromethyl)toluene, was employed.

Halogen-metal exchange from the corresponding 3-bromoderivative yields 1-(tert-butyldimethylsilyl)-3-lithioindole which reacts with electrophiles to form 3-substituted indoles. The N-silyl-3-lithioindole is of value in the synthesis of 3-substituted indoles due to the absence of ring fragmentation and rearrangement and the easy elimination of the protecting group.