Total Synthesis of Dumsin. 1. Retrosynthetic Strategy and the Elaboration of Key Intermediates from (−)-Bornyl Acetate
作者:Leo A. Paquette、Fang-Tsao Hong
DOI:10.1021/jo0301346
日期:2003.9.1
An intramolecular anionic oxy-Cope rearrangement (44 --> 46) serves as the key step in a synthetic approach to the insect antifeedant dumsin. Initial investigations clarified the manner in which (--)-bornyl acetate may be transformed into the exo-norbornenol 44. Two routes were developed to advance beyond 46. The first involved acetal 51 as a matrix that was expected to allow the elaboration of rings
Alkali Metal Counterion Control of Enolate Protonation Stereoselectivity
作者:Yang Hu、Raynauld L. Bishop、Andreas Luxenburger、Shuzhi Dong、Leo A. Paquette
DOI:10.1021/ol060761s
日期:2006.6.1
[reaction: see text] Generation of the lithium salt of the norbornenol shown (M = H) followed by quenching with aqueous NH(4)Cl solution gives predominantly the beta-epimeric ketone 6. Similar production of the potassium alkoxide leads instead to the alpha-epimer (99:1). These results reveal the potential importance of alkali metal counterions as stereocontrol elements.