Date of Award
Union College Only
Bachelor of Science
Allylic tins when reacted with aldehydes are known to be diastereoselective for the resulting homoallylic alcohols. It is believed that a diastereomeric transition state can be created if the allylic tin contains a chiral ligand. Enantiomerically enriched α-pinene was chosen for the chiral ligand and brominated by an electroptilic addition of HBr to form enantiomerically enriched endo-2-bromobornane. This was then reacted with various alkyltin anions prepared from the chlorides, R3SnCl (R=Ph, Bu, & Me). Of the alkyltin chlorides chosen Me3SnCl produced the desired product in the best yield; the others were either very slow in reacting or unreactive. The final step was the addition of an allylic group to the organotin compound. Crotyl and cinnamyl were the allylic groups chosen. Model compounds were prepared to investigate attaching crotyl and cinnamyl to tin. The cinnamyl group was chosen since it is known to go by way of a cyclic transition state, when attached to an organometallic compound and reacted with an aldehyde. In forming cinnamyldimethylisobornyltin, the chiral allylic tin, a rearrangement of the double bond on the cinnamyl group occurred and the product was a mixture of two isomers. Because of this and the very low yield, the final reaction with the aldehyde was not carried out.
Abed, Jean-Claude David, "The synthesis of allylic organotin compounds for the enantioselective formation of homoallylic alcohols" (1990). Honors Theses. 2027.