Beilstein J. Org. Chem.2010,6, 876–879, doi:10.3762/bjoc.6.103
include the following oxidative rearrangements: lead tetraacetate [3], sodium tungstate [11], tert-butyl hypochlorite [12] and N-bromosuccinimide [13]. Other approaches involve the Mannichreaction [14], ring expansion reactions [15][16], 1,3-dipolar [3 + 2] cycloadditions [17][18][19], intramolecular
[31], dimethyldioxirane (DMDO) mediated oxidation [32], and by tandem intramolecular photocycloaddition–retro-Mannichreaction [33].
The Wittig olefination–Claisen rearrangement protocol [35] provides a ready access to 4-pentenals, which have served as versatile intermediates for the synthesis of a
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as donor, and subsequently to a Mannichreaction with α-iminoglyoxylate.
Supported and heterogeneous catalysis
Chiral catalysts and ligands are often expensive and the complete separation of these components from reaction products can frequently be quite challenging. Degradation products and leaching
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Graphical Abstract
Scheme 1:
Enantioselective addition of trimethylsilyl cyanide to benzaldehyde.