ORGN 657 |
| The last decade has seen a huge advance in enantiocontrol in the Pd-catalyzed allylic substitution reactions. However, the catalytic systems developed to date generally have two important drawbacks: (i) they show a high substrate specificity and (ii) the reaction rates are usually low. In this context the research into faster and more versatile ligand systems from readily available simple starting materials is of great importance in this reaction.1 We have designed and synthesized a new family of readily available highly-modular phosphite-oxazoline ligands for the Pd-catalyzed asymmetric allylic substitution reactions (Figure 1). The introduction in the design of a π-acceptor flexible bulky biphenyl phosphite moiety is highly adventitious in the product outcome. Thus, this ligand series affords excellent reaction rates (TOF's up to > 2400 mol * (mol*h)-1) and enantioselectivities (ee's up to >99%) and, at the same time, shows a broad scope for different substrate types.2
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Asymmetric Reactions, Heterocycles, Aromatics, Combinatorial, and Physical Organic Chemistry
8:00 PM-10:00 PM, Wednesday, 31 August 2005 Washington DC Convention Center -- Hall A, Poster
Division of Organic Chemistry |
