Synthesis of Optically Active 2-Alkoxy-2<i>H</i>-pyran-3(6<i>H</i>)-ones. Their Use as Dienophiles in Diels−Alder Cycloadditions
作者:Christian A. Iriarte Capaccio、Oscar Varela
DOI:10.1021/jo0106896
日期:2001.12.1
cycloadducts 9a-c and 10a were respectively obtained with good diastereofacial selectivity (>80%). Optimized Lewis acid promoted cycloadditions led to 9a-d and 10a,c in higher yields (approximately 80%) and with higher diastereoselectivities (>94%). The major products were formed by approach of the dienes from the less hindered face of the dihydropyranones, and the minor products (such as 11a) were formed
Reactions of Diels–Alder adducts of a sugar-derived dihydropyranone leading to fused polycyclic compounds
作者:Christian A. Iriarte Capaccio、Oscar Varela
DOI:10.1016/j.carres.2004.01.008
日期:2004.4
having three or four fused rings. Reduction of the carbonyl group of the butadiene adduct (2) took place with low facial selectivity affording the alcohols 5 and 6 in 1:1.4 ratio. In contrast, a higher diastereoselection was observed for the reduction of the carbonyl of the cyclopentadiene adducts 3 and 4 to give the endo alcohols 10 and 13, respectively. The epoxidation of 6 showed low facial selectivity