Browsing by Author "Pihko, Ainoliisa J."
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- Enantioselective synthesis of a hindered furyl substituted allyl alcohol intermediate: a case study in asymmetric synthesis
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2004) Pihko, Ainoliisa J.; Lundell, Katri; Kanerva, Liisa; Koskinen, Ari M.P.In the course of the synthesis of the DEFG ring system of cneorin C 1, we were faced with the task of preparing the furyl substituted allyl alcohol 5 enantioselectively. Several different methods starting from enantioselective zinc-mediated alkylations were attempted, but none of them proved entirely satisfactory. The solution turned out to be enzymatic kinetic resolution through a highly enantioselective (E > 300) acylation in the presence of Candida antarctica lipase A. - An expedient synthesis of D-callipeltose
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2001) Pihko, Ainoliisa J.; Nicolaou, K.C.; Koskinen, Ari M.P.Methyl D-callipeltose 12 and D-callipeltose 4 were synthesized from D-glucal 5 in 10 and 11 steps, respectively. The synthesis features an azide displacement reaction of an -nosyloxy ketone 7 and a highly diastereoselective C-methylation of alpha-azido ketone 8. - Syntesis of propellane-containing natural products
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2005) Koskinen, Ari M.P.; Pihko, Ainoliisa J. - Synthesis of DEFG ring system of cneorins
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2008) Koskinen, Ari M.P.; Pihko, Ainoliisa J.The cneorins have been isolated from the xerophytic shrub Cneorum pulverulentum, which is native to the Canary Islands. They are natural products containing a [4.3.1]propellane ring system (DEFG rings) as the northern part of the molecule and a 5,5-spiroketal unit and a butenolide moiety (A ring) as the southern part. The synthesis of the DEFG ring system of the cneorins is described. The key steps include: intramolecular cyclopropanation of a diazomalonate providing the EFG ring fragment and an anionic cyclization of a sulfone yielding the [4.3.1]propellane ring system.