کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
69665 | 48786 | 2015 | 8 صفحه PDF | دانلود رایگان |
• Stereoselective cascade reactions.
• One-pot four enzymes system to provide cyclitol moieties.
• Highly stereoselective intramolecular Henry reaction.
• 11 new nitrocyclitols prepared.
One-pot multistep stereoselective cascade reactions were implemented for the straightforward synthesis of various nitrocyclitols. Two kinases, an aldolase and a phosphatase were involved in this process, together with a spontaneous intramolecular Henry reaction to provide the nitrocyclitol moiety. The CC bond formation catalysed by the aldolase and the nitroaldol reactions were key steps to build the carbocycle stereoselectively. The aldolase acceptor substrates were all 4-nitrobutanal structurally based, either hydroxylated or unsubstituted at the C2 and/or C3 positions. l-Fuculose-1-phosphate aldolase (FucA) catalysed the formation of the expected (R,R)- or d-erythro aldol, except in the case of 4-nitrobutanal, from which the epimeric (R,S)- or l-threo aldol was also formed. l-Rhamnulose-1-phosphate aldolase consistently formed the expected (R,S)- or l-threo aldol together with a minor amount of (R,R)- or d-erythro aldol. The intramolecular Henry reaction was also found to be stereoselective, occurring spontaneously once the aldol was formed due to the presence of both ketone and a terminally positioned nitro group. The combination of this set of reactions successfully furnished 11 nitrocyclitols which have not been described previously in the literature.
Figure optionsDownload as PowerPoint slide
Journal: Journal of Molecular Catalysis B: Enzymatic - Volume 114, April 2015, Pages 50–57