Stephen A. Godleski

3.3 – Nucleophiles with Allyl–Metal Complexes

Interest in π-allylpalladium chemistry has undergone incredible growth, particularly over the last decade. This growth is exemplified by the significant number of reviews on this subject that have now appeared, including several within the last few years.1–16 In light of this substantial coverage, this chapter is not intended to serve as a comprehensive review of this area of chemistry. Rather, the focus of this chapter will be on the selectivities, namely chemo-, diastereo-, regio- and enantio-selectivity, that are exhibited by π-allylpalladium chemistry. As possible, the mechanistic basis of these selectivities will be elucidated. In addition, the selection of examples provided to illustrate the nature of reactions involving π-allylpalladium complexes will be largely made from contributions that have appeared in the last decade.

Palladium assisted synthesis of 1-azaspirocycles

Abstract A facile, general route to 1-azaspirocycles utilizing a π-allyl palladium complex in the key cyclization step has been developed.

Cobalt-catalyzed selective conversion of diallylanilines and arylimines to quinolines

A variety of diallylanilines are shown to undergo cobalt-carbonyl catalyzed rearrangement to quinolines. Diallylanilines are also used as allyl transfer reagents to convert benzaldimines into quinolines. Substitution in the 2- and 3-positions of the quinoline is featured in all transformations.

Stabilization of silicenium ions by second row π-donor substituents.An ab initio study.

Abstract PH2 despite its strong inherent π-donor ability, stabilizes silicenium ions less than NH2 because of the high barrier to pyramidalization at phosphorus which destabilizes the planar H2PSi2+. HSSiH2+ and HOSiH2+ have similar stabilities while ClSiH2+ is less stable than FSiH2+.

MNDO study of phosphine- and amine-substituted silicenium ions

Abstract MNDO calculations indicate that substituted phosphines (PR 2 ) and amines (NR 2 ) are capable of providing considerable stabilization to silicenium ions.

Syntheses of (D3)-trishomocubane (pentacyclo[6,3,0,02,6,03,10,05,9]undecane) by rearrangement

(D3)-Trishomocubane (I) can be synthesized easily by aluminum bromide-catalysed isomerization of pentacyclo[5,4,0,0,2,603,10,05,9]undecane (II) or by skeletal rearrangement during aqueous HI iodination of the diol (III), followed by dehalogenation.

New approach to silver halide photography using radical cation chemistry

A new mechanism for spectral sensitization of silver halide is described, which can potentially double the sensitivity of photographic emulsions. The photooxidized sensitizing dye is trapped using an organic donor molecule, which fragments to form a cation and a reducing radical, which injects an electron into the conduction band of the silver halide. In this way, two conduction-band electrons can be produced for each absorbed photon.

Ethanonoradamantanes by rearrangement and by synthesis. Evaluation of empirical force field calculations

Empirical force field calculations predict that 2,4-ethanonoradamantane (1) and 2,8-ethanonoradamantane (2) should be the most stable tetracyclic C11H16 isomers and both should have comparable stability; experimentally, AlBr3 isomerisation yielded only (1) and (2)(also synthesised independently) but in a ratio of 97:3.

Exo/emdo soltolysis rate ratios in constrained 2-norbornyl systems

Abstract Tetracyclol[6.2.1.0 2,6 .0 5,10 ]undec-3-yl derivatives ( 6 - 8 ) show typically high tertiary exo/endo solvolysis rate ratios, but the ratios for secondary reactants are suppressed. The rate and product data support the theory of anchimeric assistance in the parent exo -2-norbornyl solvolysis.