2-Amino-4-(alkoxymethyl)-1,3-butadienes react smoothly with nonactivated aldimines derived from aromatic aldehydes in the presence of ZnCl2 as Lewis acid giving rise, with good yields and very high stereoselectivity, to substituted 4-aminotetrahydropyridines which upon hydrolysis yield 4-piperidone derivatives. Moreover, the stereochemistry of the cyclization process depends on the nature of the N-substituent of the imine.
Barluenga Jose, Aznar Fernando, Valdes Carlos, Cabal Marfa-Paz, J. Org. Chem., 58 (1993) N 12, S 3391-3396
作者:Barluenga Jose, Aznar Fernando, Valdes Carlos, Cabal Marfa-Paz
DOI:——
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HART, D. J.;KANAI, KEN-ICHI;TOHOMAS, D. G.;YANG, TENG-KUEI, J. ORG. CHEM., 1983, 48, N 3, 289-294
作者:HART, D. J.、KANAI, KEN-ICHI、TOHOMAS, D. G.、YANG, TENG-KUEI
DOI:——
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Reversal of stereochemistry in a two-step Staudinger reaction by changing the backbone protecting group. Synthesis of NH-trans-3-benzoyloxy-4-aryl-azetidinones
Changing the protecting group in the glyoxylic acid derived ketene from benzyloxy to benzoyloxy provides a simple way of switching the diastereoselectivity of the substituents on the final β-lactamring from cis to trans.