1613295-11-6Relevant articles and documents
Tosylhydrazide-promoted diastereoselective intramolecular 1,3-dipolar cycloadditions: Synthesis of tetrahydropyrrolo[3,4-c]pyrazoles
Barroso, Raquel,Escribano, Maria,Cabal, Maria-Paz,Valdes, Carlos
, p. 1672 - 1683 (2014/03/21)
A very straightforward diastereoselective synthesis of tetrahydropyrrolo[3, 4-c]pyrazoles by intramolecular 1,3-dipolar cycloaddition is described. The starting materials for the synthetic route are N-Boc-protected α-amino acids, which are first transformed into N-allyl-α-amino ketones through conventional methodologies. Then, a one-pot sequence that involves formation of a tosylhydrazone from the ketone, base-induced decomposition of the hydrazone, and intramolecular 1,3-dipolar cycloaddition of the diazo compound generated, gives rise to the bicyclic systems with total diastereoselectivity and high preservation of the enantiomeric purity. However, the analogous process employing α-amino aldehydes lacks stereoselectivity. DFT computational modeling has been carried out to account for the different behavior of the two types of systems. Copyright
