Back to Table of Contents

47142-GB1
Pd(0)-Catalyzed [3+2] Cycloadditions Involving Novel Epoxide and Aziridine Containing Trimethylenemethane Precursors

Kevin L. Jantzi, Valparaiso University

During the last year, four students and I have worked on this project.� We have synthesized a large amount of compound 1, an important intermediate in the synthesis of our desired epoxide (3) and aziridine (4) precursors for the Pd(0)-catalyzed Trimethylenemethane (TMM) cycloaddition reactions.� We have also scaled up the Swern oxidation and can routinely do the reaction on a 10 mmol scale with good results and yields.� We have also made some initial studies related to the formation of compound 4 which indicate that it may be possible to use intermediate aldehyde 2 as a precursor to both compounds 3 and 4.�

����������� Based on a large number of reactions using various conditions, it is quite clear that compound 3 does not undergo the Pd-catalyzed reactions shown below.� Apparently, the epoxide does not open to form the intermediate π-allyl palladium complex, even though similar model systems by Trost have been shown to undergo epoxide opening.� We have been able to repeat these two reactions using known precursors from the literature, so it is clear that our technique and reagents are fine.� It may be that the large TMS group of compound 3 is blocking the approach of the palladium catalyst.� In any event, we plan to use a variety of Lewis acids (e.g., TMSOAc, BF₃�OEt₂, TMSCl) to promote opening of the epoxide. ��We also plan to use a more electron rich palladium catalyst which may better promote ring opening.�

Back to top