Bimetallic Lewis Acid Template-Mediated Enantioselective Hetero-Diels-Alder Reactions of 4-Siloxy-2,4-pentadienols

Progress in Lewis Acid Template-Mediated Diels-Alder Reaction

“…In this case, chiral dihydropyran was obtained in 95% yield with 99% ee. The authors investigated hetero-Diels-Alder reaction of 2,4-pentadienol and benzaldehyde using Lewis acid template (Scheme 16) [50]. After various investigations of the silyl group, Lewis acid, or biaryl ligands, etc.…”

Catalytic Asymmetric Total Synthesis of Exiguolide

“…Given the tetrahydropyran motif, one of the attractive strategies is the asymmetric hetero-Diels-Alder reactiono f aldehyde 10 and diene 11 catalyzed by aL ewis acid template, which we have previously developed. [13] An alternative method involves Prins reactiono f12,w hich would be readily derived from C 2 -symmetric diol 13.…”

“…[20] This methodw as also effective for the hetero-Diels-Alder reaction. [13] The hetero-Diels-Alder reactions of 4-siloxy-2,4-pentadienol and dienophiles catalyzed by the chiralL ewis acid H 8 -BINOLt emplate allow an expeditious access to chiral dihydropyrans. Thus, our initial efforts focusedo nt he Lewis acid template-catalyzed hetero-Diels-Alder reaction of compound 10 and diene 11 for the formation of compound 9.…”

“…[34] Finally,h ydrostannylationo f 2 followed by Stille coupling of 34 with known iodide 35 [5] afforded couplingp roduct in good yield as a Z/E -mixture, which was purified by HPLC to furnish pure (À)-exiguolide (1). The synthetic sample exhibited spectral data ( 1 Ha nd 13 CNMR, [a] D ) identicaltot hose reportedf or natural specimen.…”