ORGN 25 |
| A palladium catalyzed C-H bond functionalization system that operates under ambient and aerobic conditions has been developed to alkenylate pyrroles with control of regioselectivity. A steric and electronic control strategy can be used to influence positional control in the C-H functionalization process that results in either the C2 or C3 alkenylated products. Air, oxygen or tBuOOBz can be used as reoxidant in this mild process, and the reaction works on a range of substrates. The aerobic system can be applied to annulation strategies, where regioselectivity is controlled to produce cyclization at either C2 or C3, thus forming diverse pyrrole architectures. The utility of this methodology was investigated though the synthesis of natural product, oxo-rhazinilam. The strategy involves two metal catalyzed pyrrole C-H functionalization steps, namely a one-pot C3 selective boronylation-Suzuki arylation sequence and a C2 selective pyrrole alkenylation, which allows rapid generation of complexity from linear precursors.
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Metal-Mediated Reactions and Syntheses
8:00 AM-12:00 PM, Sunday, August 19, 2007 BCEC -- 254 A/B, Oral
Division of Organic Chemistry |
