Facilitation of electron transfer substitution processes at a saturated carbon atom by the cyano group
Abstract
This thesis is concerned with the question: Can the cyano group behave like a nitro group and foster substitution at a saturated carbon atom via a one electron transfer chain mechanism in which radical anions and free radicals are intermediates? Consequently the chemistry of the p-cyanobenzyl, p-cyanocumyl, and o,p-dicyanocumyl systems were investigated. It transpires that a cyano group is capable of facilitating radical anion substitution at a saturated carbon atom. All told eleven such reactions were found; they proceed in yields ranging from 66% to 94%. In eight of these cases mechanistic studies employing di-t-butylnitroxide and nitroaromatics provide clear evidence for the chain mechanism in which radical anions and free radicals are intermediates. Consonant with this mechanistic assignment is the fact that these processes are accelerated by the light of two ordinary 20 watt fluorescent lamps. Of special interest are those cases in which there is no nitro function in either component of the reaction mixture. Thus, o,p-dicyano-$\alpha$-phenylsulfonylcumene I and the sodium salt of methylmalonic ester react completely in 24 hours at room temperature and give a 70% yield of pure alkylate. And treatment of sulfone I with sodium thiophenoxide at 25$\sp\circ$C for 10 minutes results in replacement of the sulfone function by thiophenyl in 80% yield. When o,p-dicyano-$\alpha$-nitrocumene II is treated with sodium cyanide none of the expected tricyano compound was detected. Instead, the reduction product, o,p-dicyanocumene, is isolated in 55% yield after 2 hours and 20 minutes at room temperature. In addition to the reaction of nitro compound I with sodium cyanide there are indications that still another process, which produces water soluble products, intrudes when either I or II are exposed to the methylmalonic ester anion.
Degree
Ph.D.
Advisors
Kornblum, Purdue University.
Subject Area
Chemistry
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