OH-Metal hydrogen bond in Pd- and Ir-catalyzed allylic alkylations
2006 (English)In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 2006, ORGN-259- p.Conference paper (Other academic)
Phosphinooxazolines carrying 4-hydroxybenzyl and 4-methoxybenzyl substituents exhibit contrasting behavior in Pd- and Ir-catalyzed allylic alkylations. Whereas catalysts with the methoxy-contg. ligand generally provide products with high ee's, use of catalysts prepd. from the hydroxy contg. ligand results in products with low ee's or even racemates. DFT calcns. suggest the presence of a hydrogen bond with Pd(0) as proton acceptor in the hydroxy contg. olefin Pd(0) complexes, which induces a conformational change in the ligand leading to different stereoselectivity. We have previously obsd. the same kind of dramatic changes of enantioselectivities in palladium-catalyzed allylations upon methylation of hydroxy-contg. pyridinooxazolines and bisoxazolines.
Place, publisher, year, edition, pages
2006. ORGN-259- p.
, Abstracts of papers of the american chemical society, ISSN 0065-7727
IdentifiersURN: urn:nbn:se:kth:diva-71036ISI: 000207781608341OAI: oai:DiVA.org:kth-71036DiVA: diva2:486428
232nd ACS National Meeting, San Francisco, CA
QC 201202222012-01-302012-01-302012-02-22Bibliographically approved