501-96-2Relevant articles and documents
STEREOCHEMISTRY OF 4-ARYL-2-BUTANOLS FROM HIMALAYAN TAXUS BACCATA
Das, B.,Takhi, M.,Kumar, H. M. Sampath,Srinivas, K. V. N. S.,Yadav, J. S.
, p. 697 - 700 (1993)
4-(4'-Hydroxyphenyl)-2R-butanol, 4-(3',4'-dihydroxyphenyl)-2R-butanol and 4-(3'-methoxy-4'-hydroxyphenyl)-2R-butanol have been isolated from the needles of Himalayan Taxus baccata.These two compounds have not previously been reported in stereospecific forms.Their stereochemistry has been determined by enzymatic reduction of their corresponding 2-butanones.Key Word Index - Taxus baccata; Taxaceae; 4-aryl-2-butanol, stereochemistry; enzymatic reduction; baker's yeast.
Deracemization and Stereoinversion of Alcohols Using Two Mutants of Secondary Alcohol Dehydrogenase from Thermoanaerobacter pseudoethanolicus
Hamdan, Samir M.,Musa, Musa M.,Nafiu, Sodiq A.,Takahashi, Etsuko,Takahashi, Masateru
supporting information, (2020/07/24)
We developed a one-pot sequential two-step deracemization approach to chiral alcohols using two mutants of Thermoanaerobacter pseudoethanolicus secondary alcohol dehydrogenase (TeSADH). This approach relies on consecutive non-stereospecific oxidation of alcohols and stereoselective reduction of their prochiral ketones using two mutants of TeSADH with poor and good stereoselectivities, respectively. More specifically, W110G TeSADH enables a non-stereospecific oxidation of alcohol racemates to their corresponding prochiral ketones, followed by W110V TeSADH-catalyzed stereoselective reduction of the resultant ketone intermediates to enantiopure (S)-configured alcohols in up to > 99 percent enantiomeric excess. A heat treatment after the oxidation step was required to avoid the interference of the marginally stereoselective W110G TeSADH in the reduction step; this heat treatment was eliminated by using sol-gel encapsulated W110G TeSADH in the oxidation step. Moreover, this bi-enzymatic approach was implemented in the stereoinversion of (R)-configured alcohols, and (S)-configured alcohols with up to > 99 percent enantiomeric excess were obtained by this Mitsunobu-like stereoinversion reaction.
Asymmetric synthesis of enantiomerically pure zingerols by lipase-catalyzed transesterification and efficient synthesis of their analogues
Kitayama, Takashi,Isomori, Sachiko,Nakamura, Kaoru
, p. 621 - 627 (2013/07/19)
The achiral zingerone 1, readily available from ginger, can be easily transformed into chiral derivatives. Zingerol 2, a reduced product of zingerone 1 is expected to be an important new medicinal lead compound. We have achieved a concise synthesis of optically active zingerol (R)-2 and (S)-2 by the lipase-catalyzed stereoselective transesterification of racemic 2. Under the optimized conditions, a lipase from Alcaligenes sp. (Meito QLM) and vinyl acetate in i-Pr2O or hexane at 35 C within 1 h gave the alcohol (S)-2 and the acetate (R)-9 with high enantioselectivity without producing acetylated by-products. Since optically active (S)-2 and (R)-9 were obtained through lipase-catalyzed transesterification, other enantiomerically pure novel compounds could all be synthesized.
Concise enantioselective synthesis of the ten-membered lactone cephalosporolide G and its C-3 epimer
Barradas, Silvia,Urbano, Antonio,Carreno, M. Carmen
body text, p. 9286 - 9289 (2010/04/03)
A short and highly stereo-selective sequence for the first enantioselective total synthesis of the naturally occurring 10-membered lactone, which was obtained in only eight steps, was reported. The macrolactone ring was carried out by the use of a high-yielding pyridinium chlorochromate (PCC)-mediated oxidative cleavage of a bicyclic intermediate, generated in a domino sequence from a p-peroxyquinol. The synthesis was started with (-)-rhododendrol, which was obtained by enzymatic resolution of the racemic derivative. Phenol (R)-5 was submitted to an oxidative dearomatisation process with singlet oxygen, generated from Oxone in the presence of NaHCO3. The treatment of compound peroxyquinol with para-toluene sulfonic acid followed by Triton B gave, in one step and 49% yield, the tricyclic epoxide bicyclic derivative. A similar route was employed for the synthesis of the C-3 diastereoisomer of the natural product, which was obtained in only 7 steps and 15.2% overall yield.