119067-60-6Relevant articles and documents
Highly regio- and enantioselective reduction of 3,5-dioxocarboxylates
Wolberg, Michael,Hummel, Werner,Wandrey, Christian,Mueller, Michael
, p. 4306 - 4308 (2000)
Only the keto group in position C-5 is reduced in the enzymatic reduction of 3,5-dioxocarboxylates by the alcohol dehydrogenase of Lactobacillusbrevis (LBADH; see scheme). The strategy of nature for manipulating β-keto metabolites inspired the development of a chemoenzymatic approach to virtually enantiopure 3,5-dihydroxycarboxylate building blocks. The crucial enzymatic step can be performed on an attractively large scale.
Synthesis of highly substituted pyranonaphthalene spiroketals related to the griseusins using a Hauser-Kraus annulation strategy
Naysmith, Briar J.,Furkert, Daniel,Brimble, Margaret A.
, p. 1199 - 1206 (2014/02/14)
The synthesis of an advanced pyranonaphthalene spiroketal as an intermediate for the total synthesis of griseusin B is described. A one-pot Hauser-Kraus annulation-methylation via reaction of a highly-substituted enone with a cyanophthalide was employed to construct the naphthalene framework. Other key steps include Sharpless asymmetric dihydroxylation of a (Z)-alkene and an HF-pyridine mediated double TBS deprotection-spirocyclisation.
Concise total synthesis of botryolide B
Mohapatra, Debendra K.,Umamaheshwar, Gonela,Rao, M. Mallikarjuna,Umadevi, Deivasigamani,Yadav, Jhillu S.
, p. 8335 - 8340 (2014/02/14)
An efficient total synthesis of botryolide B was achieved in 9 longest linear steps with 22% overall yield via esterification of a carboxylic acid with an alcohol fragment and a ring closing metathesis (RCM) reaction as pivotal steps to construct the macrolactone ring system. Our novel approach for the synthesis of the 2-alkene-1,5-diol fragment was achieved by a ring closing metathesis reaction followed by a reductive opening strategy, whereas the carboxylic acid fragment was accessed from commercially available (R)-(+)-α-hydroxy-γ-butyrolactone in three steps.
Enantiomerically pure allylboronic esters as versatile reagents in the enantioselective synthesis of dihydro-α-pyrone-containing natural products
Bartlett, Sean,Boese, Dietrich,Ghori, Daniel,Mechsner, Bastian,Pietruszka, Joerg
, p. 1106 - 1114 (2013/05/21)
A short and efficient enantio- and diastereoselective synthesis of different representatives from the class of dihydro-α-pyrone natural products, including both enantiomers of goniothalamin, massoia lactone, parasorbic acid, and some derivatives is presented. It is based on the application of enantiopure α-chiral allylboronic esters in allyl additions. Georg Thieme Verlag Stuttgart New York.
Synthesis of 6,6′-binaphthopyran-2-one natural products: Pigmentosin A, talaroderxines A and B
Grove, Charles I.,Di Maso, Michael J.,Jaipuri, Firoz A.,Kim, Michelle B.,Shaw, Jared T.
, p. 4338 - 4341,4 (2012/12/11)
Efficient and stereoselective syntheses of pigmentosin A, talaroderxine A, and its diastereomer talaroderxine B are reported. The binaphthyl ring system is assembled by vanadium-catalyzed phenolic coupling of tricyclic precursors. These key intermediates were prepared by Michael-Dieckmann annulation of a protected orsellinate ester, with the requisite pyranones accessed by a new variant of Ghosez's sulfone-epoxide annulation. Preliminary biological experiments are reported for pigmentosin.
Synthesis of 6,6′-binaphthopyran-2-one natural products: Pigmentosin A, talaroderxines A and B
Grove, Charles I.,Di Maso, Michael J.,Jaipuri, Firoz A.,Kim, Michelle B.,Shaw, Jared T.
, p. 4338 - 4341 (2013/01/14)
Efficient and stereoselective syntheses of pigmentosin A, talaroderxine A, and its diastereomer talaroderxine B are reported. The binaphthyl ring system is assembled by vanadium-catalyzed phenolic coupling of tricyclic precursors. These key intermediates were prepared by Michael-Dieckmann annulation of a protected orsellinate ester, with the requisite pyranones accessed by a new variant of Ghosez's sulfone-epoxide annulation. Preliminary biological experiments are reported for pigmentosin.
Synthesis of (-)-viriditoxin: A 6,6′-binaphthopyran-2-one that targets the bacterial cell division protein FtsZ
Park, Young Sam,Grove, Charles I.,Gonzalez-Lopez, Marcos,Urgaonkar, Sameer,Fettinger, James C.,Shaw, Jared T.
supporting information; experimental part, p. 3730 - 3733 (2011/05/15)
(Chemical Equation Presented) Remote control: Vanadium catalysts provide the key to synthesizing the bacteria-fighting natural product viriditoxin. An achiral catalyst shows modest levels of remote diastereocontrol induced by the lactone stereogenic center and chiral catalysts can be used to enhance or reverse this inherent selectivity.
Biocatalytic reduction of β,δ-diketo esters: A highly stereoselective approach to all four stereoisomers of a chlorinated β,δ-dihydroxy hexanoate
Wolberg, Michael,Hummel, Werner,Mueller, Michael
, p. 4562 - 4571 (2007/10/03)
A stereoselective chemoenzymatic synthesis of all four stereoisomers of tert-bulyl 6-chloro-3,5-dihydroxyhexanoate (6a) is presented. The key step of the sequence is a highly regio-and enantioselective single-site reduction of tert-butyl 6-chloro-3,5-dioxohexanoate (1a) by two enantiocomplementary biocatalysts. Alcohol dehydrogenase from Lactobacillus brevis (recLBADH) afforded a 72% yield of enantiopure tert-butyl (5)-6-chloro-5-hydroxy-3-oxohexanoate [(S)-2a]. The enantiomer (R)-2a was prepared with 90-94% ee by Baker's yeast reduction in a biphasic system (50% yield). Both biotransformations were performed on a gram scale. The β-keto group of the enantiomeric δ-hydroxy-β-keto esters 2a thus obtained was reduced by synand anti-selective borohydride reductions. Permutation of the reduction methods yielded all four stereoisomers of the crystalline target compound 6a (≥99.3% ee, dr≥205:1), which is a versatile 1,3-diol building block. recLBADH accepts a variety of β,δ-diketo esters as was determined in a photometric assay. tert-Butyl 3,5-dioxohexanoate (1b) and tert-butyl 3,5-dioxoheptanoate (1c) were reduced on a preparative scale as well to afford the corresponding δ-hydroxy-β-keto esters (R)-2b and (R)-2c with 99.4% ee and 98.1% ee, respectively. Wiley-VCH Verlag GmbH, 2001.
Asymmetric synthesis of goniothalamin, hexadecanolide, massoia lactone, and parasorbic acid via sequential allylboration-esterification ring-closing metathesis reactions
Ramachandran, P. Veeraraghavan,Reddy, M. Venkat Ram,Brown, Herbert C.
, p. 583 - 586 (2007/10/03)
Acrylic esters of homoallylic alcohols prepared in 92-97% ee via the asymmetric allylboration of appropriate aldehydes with B- allyldiisopinocampheylborane, when refluxed in dichloromethane in the presence of 10 mol% of Grubbs' catalyst provided the natural enantiomers of (S)-(+)-parasorbic acid, (R)-(-)-massoia lactone, and (R)-(+)goniothalamin. (S)-(-)-Hexadecanolide was prepared by hydrogenating the corresponding lactenone synthesized using the above sequence. (C) 2000 Elsevier Science Ltd.
One-pot and sequential asymmetric hydrogenation of β,δ-diketoesters into functionalized 1,3-diols: From anti- to syn-stereoselectivity
Blandin, Veronique,Carpentier, Jean-Francois,Mortreux, Andre
, p. 3421 - 3427 (2007/10/03)
The asymmetric hydrogenation of methyl 3,5-dioxohexanoate (1) into mixtures of 3,5-dihydroxyesters (2) and 3-hydroxylactones (3) has been reinvestigated with a variety of ruthenium catalysts. Catalysts bearing diphosphanes which possess axial chirality such as (S)-MeO-Biphep give predominantly (3R,5S)-anti-2 in up to 78% de and 95% ee, affording an efficient synthesis of (S)-6-methyl-5,6-dihydro-2-pyrone [(S)-5] in up to 95% enantiomeric excess. On the contrary, some Ru-{amidophosphane-phosphinite} complexes catalyze sluggishly the formation of syn-2 in up to 92% de but with poor enantiomeric excesses. In all cases, methyl (R)-3-hydroxy-5-oxohexanoate [(R)-11] is the exclusive primary hydrogenation product, which can be isolated in high yields and enantiomeric excesses up to 78%. Further hydrogenation of enantiomerically enriched (R)-11 in a separate experiment affords (3R,5R)-syn-2 in high diastereomeric and enantiomeric excesses (up to 80% and 98%, respectively), provided a Ru-(R)-Binap-type catalyst is used.
