An interesting issue of Diels-Alder selectivity discovered en route to 11-O-debenzoyltashironin.
The hypervalent iodine-mediated oxidative dearomatization/Diels-Alder cascade was examined in the context of the natural product 11-O-debenzoyltashironin. Interestingly, the regioselectivity of the Diels-Alder reaction can be completely switched by changing the dienophile. Trapping of allyl alcohols during the oxidative dearomatization gives rise to the five-membered acetal, while trapping of allenyl alcohols results in the six-membered acetal. [reaction: see text]
Cook
Silas P
SP
Department of Chemistry, Columbia University, Havemeyer Hall, 3000 Broadway, New York, NY 10027, USA.
Danishefsky
Samuel J
SJ
D000438:Alcohols; D000447:Aldehydes; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis; D001952:Bridged-Ring Compounds / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D007455:Iodine / Q000737:chemistry; D010084:Oxidation-Reduction
C516856:11-O-debenzoyltashironin; D000438:Alcohols; D000447:Aldehydes; D001643:Bridged Bicyclo Compounds; D001952:Bridged-Ring Compounds; D007202:Indicators and Reagents; D007455:Iodine