Did you know that baker's yeast can bee used to reduce the double bond of the nitrostyrenes?
Then you still haven’t read
Post 108516
(dormouse: "A new reducing agent for nitrostyrenes: bakers yeast! -Labrat", Novel Discourse).
Unfortunatelly that thread is closed so I’m uploading these papers in a new one. Maybe somebee can also upload some other pertaining papers cited in the old thread?
Asymmetric reduction of nitroalkenes with baker’s yeast.Yasushi Kawai, Yoshikazu Inaba and Norihiro Tokitoh
Tetrahedron: Asymmetry 12 (2001) 309–318.
(the experimental was already posted by
Post 352999
(foxy2: "Asymmetric reduction of nitroalkenes with baker's ...", Novel Discourse))
Abstract: Various alpha,beta-disubstituted and trisubstituted nitroalkenes were chemoselectively reduced with baker’s yeast to the corresponding nitroalkanes. Stereoselectivities of the reduction of a,b-disubstituted nitroalkenes were modest to low, and e.e.s up to 52% were obtained. Trisubstituted nitroalkenes could be reduced to the corresponding nitroalkanes with excellent enantioselectivities, moderate diastereoselectivities and in good yield.
More, but this time using the encime:
Asymmetric synthesis of a nitroalkane by the use of novel nitroalkene reductases from baker’s yeast.Yasushi Kawai, Yoshikazu Inaba, Motoko Hayashi and Norihiro Tokitoh
Tetrahedron Letters 42 (2001) 3367–3368.
Abstract: Two kinds of novel nitroalkene reductases were isolated from baker’s yeast. Reduction of a trisubstituted nitroalkene by these reductases afforded the corresponding nitroalkane with excellent enantioselectivity, moderate diastereoselectivity, and in good yield.
The good old yellow encime
– interesting kinetic studies:
Old Yellow Enzyme: Stepwise reduction of nitroolefins and catalysis of aci-nitro tautomerization.Younus Meah and Vincent Massey
PNAS 97 (2000) 10733–10738.
PDF:
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=27092&action=stream&blobtype=pdf
HTML:
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=27092
Abstract: The Old Yellow Enzyme has been shown to catalyze efficiently the NADPH-linked reduction of nitro-olefins. The reduction of the nitro-olefin proceeds in a stepwise fashion, with formation of a nitronate intermediate that is freely dissociable from the enzyme. The first step involves hydride transfer from the enzyme-reduced flavin to carbon 2 of the nitro-olefin. The protonation of the nitronate at carbon 1 to form the final nitroalkane product also is catalyzed by the enzyme and involves Tyr-196 as an active site acidybase. This residue also is involved in aci-nitro tautomerization of nitroalkanes, the first example of a nonredox reaction catalyzed by the enzyme.