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Intramolecularly Sn-N Coordinated Organotin Hydrides

Komsta Z., Cmoch C., Stalinski K.

Polish Journal of Chemistry

2006

Vol. 80, nr 8

1259-1292

In recent years, internally Sn-N coordinated organotin hydrides have found an application in organic syntheses, which involve radical chain reactions. Unique reactivity of such hydrides suggests the potential of intramolecular coordination for the control of radical reactions. When the tin hydrides are used in the presence of Lewis acids single- enatiomer outcomes are accessible. This opens a new aspect of free radical chemistry. The intramolecular Sn-N coordination enhances also nucleophilic character of the tin hydrides in reduction of ketones under mild reaction conditions. The occurrence of intramolecular interaction between the nitrogen and tin atoms can be additionally based on the changes in the characteristic values of the 1H, 13C, 15N and117/119Sn NMR parameters and their interrelations.

Stereoselection at the Steady State within radicals - How far can we go ?

Staliński K.

Polish Journal of Chemistry

2004

Vol. 78 / nr 5

611-622

Stereoselection at the steady state is a process, which results from a complex interplay of reaction pathways that diverge and reconverge at various points. Therefore, it can be considered as a manipulation of stereocontrol mainly by reaction topography. The advantages of this process are at least twofold: First, stereoconvergence allows the system to exceed the yield of the initial stereoconvergent event, where stereomeric transition states compete. Second, a successive resolution of the reactive intermediates by chemoselective events allows the system to generate high stereomeric excess, practically without any stereoselective competition. While illustrated with radicals, the process may prove useful in other fields of chemistry.