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Tesi etd-05022007-100806


Thesis type
Tesi di dottorato di ricerca
Author
Rocchiccioli, Silvia
email address
silvia79@dcci.unipi.it
URN
etd-05022007-100806
Title
Substrate-Induced Diastereoselectivity in Rhodium-Catalyzed Hydroformylation
Settore scientifico disciplinare
CHIM/06
Corso di studi
SCIENZE CHIMICHE
Commissione
Relatore Prof. Lazzaroni, Raffaello
Parole chiave
  • hydroformylation
  • Diastereoselectivity
  • chiral olefins
  • rhodium-catalyst
Data inizio appello
15/02/2007;
Consultabilità
parziale
Data di rilascio
15/02/2047
Riassunto analitico
The object of this Ph.D. thesis is an investigation on the substrate-controlled diastereoselectivity in rhodium-catalyzed hydroformylation of open-chain chiral substrates. Some cases of 1,3- and 1,2-asymmetric induction are reported starting from chiral vinyl- and allyl- alkenes and carrying out the hydroformylation reaction with an unmodified rhodium catalyst. Vinyl olefins containing an alkoxy group showed an exceptional 1,3-asymmetric induction (97/3) when a phenyl ring is linked to the stereogenic center. C-allylglycosides showed different levels of diastereoselectivity depending on the structure of the sugar-ring and the highest level of 1,3-asymmetric induction has been obtained in the case of the ƒÑ-C-allyl-glucoside, which gave 70% d.e. A different level of 1,2-asymmetric induction was observed in both chiral allylpyrroles and allylbenzenes as the steric hindrance of the alkyl chain was varied, providing diastereomeric excesses also up to 70%. Two different pyrrolylalkenes with an acetyl group linked to the ƒÒ-position of the pyrrole ring were also examined and an 8-hydroxy-5,6,7,8-tetrahydroindolizine was obtained via a complete 1,3-asymmetric induction in a domino process under oxo conditions. Theoretical investigations have also been employed in an effort to cast light on the reaction mechanism.
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