jo300806y_si_002.cif (13.23 kB)
Download file

Selective “One-Pot” Synthesis of Functionalized Cyclopentenones

Download (13.23 kB)
posted on 20.07.2012, 00:00 by Teresa Varea, Ana Alcalde, Carolina López de Dicastillo, Carmen Ramírez de Arellano, Fernando P. Cossío, Gregorio Asensio
Double addition (1,2–1,4) of vinyl magnesium bromide to squaric acid derivatives allows the preparation of polyoxygenated cyclopentenones (8) in a “one-pot” procedure. The reaction occurs through the intermediate formation of octatetraenes (6). Protonation of this latter intermediate at −78 °C with TFE occurs selectively at the vinyl CH2 closer to the metallic centers. DFT studies of the cyclization step justify the observed diastereoselectivity.