1,3 Dipolar cycloadditions of azomethine ylides with aromatic aldehydes. syntheses of 1-oxapyrrolizidines and 1,3-oxazolidines.

1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides with Carbonyl Dipolarophiles Yielding Oxazolidine Derivatives

“…A more detailed account of their work appeared in 1988, where proline (50) was reacted with various aromatic aldehydes 2 to afford, with complete regioselectivity, the hexahydropyrrolo[2,1-b]oxazoles 52 and 53, with the trans-2,3-oxazolidine 52 being either the exclusive or major stereoisomer formed [67][68][69]. The stereoselectivity of the cycloaddition was governed by both the ylide stereochemistry, with the anti-azomethine ylide 51 being favored, and the mutual orientation of the dipole and dipolarophile (Scheme 12, Table 7).…”

Use of (S)‐5‐(2‐Methylpyrrolidin‐2‐yl)‐1H‐tetrazole as a Novel and Enantioselective Organocatalyst for the Aldol Reaction

“…The pyrrolizidine 14 has previously been reported by Orsini et al [16] as a mixture of diastereomers from reaction of proline 1 with 11 in DMSO. List and Barbas III carried out their reactions in an excess of acetone in order to circumvent this undesired reaction.…”

Simple and efficient routes to substituted oxazolidine and spiro-oxindole systems by one-pot synthetic strategies

“…Of the different strategies to synthesise the oxazolidine ring-system, 1,3-dipolar cycloaddition is a leading technique [26][27][28][29][30]. In the present work, an interesting route utilising 1,3-dipolar cycloaddition has been used to synthesise oxazolidines [31][32][33][34]. The mechanism consists of the formation of the azomethine ylide in situ, followed by cycloaddition.…”

“…Our longstanding interest in 1,3-dipolar cycloaddition [41][42][43][44][45] led us to turn our attention on the direct synthesis of oxazolidine moieties by cycloaddition of non-stabilised azomethine ylides with carbonyl compounds. Orsini et al [32] and Felluga et al [33] had reported direct cycloaddition of azomethine ylides with carbonyl compounds. In the present work we have extensively studied reactions with aryl aldehyde as carbonyl compound to generate new stereocenters in the cycloadduct(s).…”