A Sc(OTf)3-catalyzed highly diastereoselective one-pot sequential [3 + 3] dipolar cycloaddition reaction of aldehyde or ketone, N-alkyl hydroxylamine, and spirocyclopropyl oxindole is developed, allowing facile construction of spirocyclic oxindole-tetrahydro-1,2-oxazines with sufficient structural diversity. The corresponding catalytic enantioselective one-pot protocol of aldehydes is also reported
Metal-free C(sp<sup>3</sup>)–H bond sulfonyloxylation of 2-alkylpyridines and alkylnitrones
作者:Chang-Sheng Wang、Pierre H. Dixneuf、Jean-François Soulé
DOI:10.1039/c8ob01075g
日期:——
Pyridin-2-ylmethyl tosylate derivatives are obtained in high yields from 2-alkylpyridine 1-oxides via a [3,3]-sigmatropicrearrangement of the adduct between 2-alkylpridine 1-oxides with benzenesulfonyl chlorides. Moreover, alkylnitrones also undergo [3,3]-sigmatropicrearrangement to give α-tosylated ketones after hydrolysis. Substitution reactions with nucleophiles then lead to diverse useful functionalizations