Solid-phase access to polyhydroxypyrrolizidines by 1,3-dipolar cycloaddition of (S)-3-alkoxypyrroline N-oxide to maleate and crotonate derivatives

A Concise Total Synthesis of (+)‐Heliotridine

“…Moreover, the carbethoxy and the alkyl groups drive the orbital interactions which lead to the complete regioselectivity. Compound 4 was very unstable, it could not be isolated, and it was directly treated with Raney Nickel and H 2 to give the enantiomerically pure pyrrolizidine derivative 5 in a 46% overall yield from 2 (Scheme ) 10,11…”

3-Benzyl-3-hydroxy-2-phenyl-3H-indole 1-oxide

“…For the use of nitrones in the spin-trapping technique and in organic synthesis, see: Janzen (1971); Zubarev (1979); Balasubramanian (1985); Pisaneschi et al (2002); Jones et al (2000); Bernotas et al (1999); Ali & Wazeer (1988); Merino (2005); Chiacchio et al (2006); Revuelta et al (2008); Astolfi et al (2003); Greci et al (2001); Tommasi et al (1999); Bruni et al (1998). For a related structure, see: Yamada et al (2003).…”

“…Although the most used nitrones in cyclization reactions are acyclic, several papers have appeared in the last two decades describing cycloaddition reactions with cyclic nitrones (Pisaneschi et al, 2002;Jones et al, 2000;Bernotas et al, 1999;Ali & Wazeer, 1988). Significant advances have been described in the use of nitrones derived from sugars and aminoacids for the synthesis of interesting biological compounds including aminoacids, amino alcohols and nucleoside analogs (Merino, 2005).…”

CC Bond‐Forming Reactions

“…Enantiopure (S)-3-alkoxypyrroline N-oxide (170), on the other hand, has been exploited in stereoselective cycloaddition reactions with solid-supported unsaturated esters (169) [266]. A both regio-and stereoselective cycloaddition took place in this case, affording the desired compound (171) as a single isomer (Scheme 36).…”