- Asymmetric synthesis of goniothalamin, hexadecanolide, massoia lactone, and parasorbic acid via sequential allylboration-esterification ring-closing metathesis reactions
-
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.
- Ramachandran, P. Veeraraghavan,Reddy, M. Venkat Ram,Brown, Herbert C.
-
-
Read Online
- ALLYLSILANES IN ORGANIC SYNTHESIS; STEREOSELECTIVE HYDROXYLACTONISATION OF CHIRAL AMIDE-ALLYLSILANES
-
The amide-allylsilanes (1) and (10) undergo stereoselective hydroxylactonisation on treatment with m-CPBA; the major products from (1) and (10) were converted into parasorbic acid (9) and the carpenter bee pheromone (13) respectively.
- Russell, Andrew T.,Procter, Garry
-
-
Read Online
- Synthesis of γ- and δ-lactone natural products by employing a trans-cis isomerization/lactonization strategy
-
Alkaline hydrolysis of 4-hydroxy- or/and 5-hydroxy-(2E)-alkenoate followed by acid treatment gave the corresponding (2E)-alkenoic acids which were subjected to lactone formation reaction without further purification. The crude acids were treated with 2,4,6-trichlorobenzoyl chloride in pyridine to afford ?-lactone or d-lactone, respectively, accompanied by trans-cis isomerization. By this procedure, (±)-(4,5)-trans-5-benzyloxy- 2-hexen-4-olide (90% overall yield), (S)-5-hydroxy-2-penten-4-olide (86% overall yield), (4S,5R)-5- hydroxy-2-hexen-4-olide (86% overall yield), (4R,5S)-5-hydroxy-2-hexen-4-olide (82% overall yield), (S)- parasorbic acid (58% overall yield) and natural product, (5R,7S)-7-hydroxy-2-octen-5-olide (euscapholide: 20% overall yield) were synthesized.
- Ono, Machiko,Kato, Keisuke,Akita, Hiroyuki
-
-
Read Online
- SYNTHESIS OF PARASORBIC ACID, THE COMPONENT OF SORBUS AUKUPARIA L.
-
Parasorbic acid ((5s)-(+)-hexen-5-olide) was synthesized from ethyl acetoacetate by utilizing its baker's yeast reduction.
- Sato, Tsuguo
-
-
Read Online
- Baker's Yeast Mediated Bioreduction of Prochiral Ketones Having 6-(4-Oxo-1,3-dioxinyl) Group
-
Prochiral ketones having 6-(4-oxo-1,3-dioxinyl) group as one terminal unit by fermenting baker's yeast gave chiral alcohols, which could be convertible to optically active hydroxyesters, β-ketoesters, and lactones.
- Sakaki, Jun-ichi,Suzuki, Miwako,Kobayashi, Satoshi,Sato, Masayuki,Kaneko, Chikara
-
-
Read Online
- Synthetic studies on marineosins based on a direct coupling reaction of pyrrole and δ-lactone
-
A promising precursor of marineosins A and B, unusual macrocyclic pyrrole and spiroiminal alkaloids isolated from marine microorganism has been synthesized employing a direct coupling of pyrrole and δ-lactone.
- Fukuda, Hayato,Hatakeyama, Susumi,Ishihara, Jun,Komine, Keita,Morii, Yuki,Suga, Akihisa,Yamamoto, Kohei
-
-
- Twofold polyketide branching by a stereoselective enzymatic Michael addition
-
The versatility of the branching module of the rhizoxin polyketide synthase was tested in an in vitro enzyme assay with a polyketide mimic and branched (di)methylmalonyl-CoA extender units. Comparison of the products with synthetic reference compounds revealed that the module is able to stereoselectively introduce two branches in one step by a Michael addition-lactonisation sequence, thus expanding the scope of previously studied PKS systems.
- Heine, Daniel,Sundaram, Srividhya,Bretschneider, Tom,Hertweck, Christian
-
supporting information
p. 9872 - 9875
(2015/06/16)
-
- Enantiomerically pure allylboronic esters as versatile reagents in the enantioselective synthesis of dihydro-α-pyrone-containing natural products
-
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.
- Bartlett, Sean,Boese, Dietrich,Ghori, Daniel,Mechsner, Bastian,Pietruszka, Joerg
-
p. 1106 - 1114
(2013/05/21)
-
- Enantioselective synthesis of the 3C-protease inhibitor (-)-thysanone by a Staunton-Weinreb annulation strategy
-
The total synthesis of (-)-thysanone is described. The key step involves the addition of an o-toluate anion to a lactone to create the naphthopyran framework (Staunton-Weinreb annulation). This synthesis further confirms the absolute stereochemistry of th
- Sperry, Jonathan,Tsz, Ying Yuen,Brimble, Margaret A.
-
experimental part
p. 2561 - 2569
(2009/12/25)
-
- One-pot and sequential asymmetric hydrogenation of β,δ-diketoesters into functionalized 1,3-diols: From anti- to syn-stereoselectivity
-
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.
- Blandin, Veronique,Carpentier, Jean-Francois,Mortreux, Andre
-
p. 3421 - 3427
(2007/10/03)
-
- A concise synthesis of (S)-(+)-5,6-2H-pyran-2-one via hydrozirconation- carbonylation-demetallation of O-benzyl (S)-(-)-4-pentyn-2-ol
-
A simple synthetic approach to α,β-unsaturated δ-lactones has been devised from the hydrozirconation of O-protected homopropargyl alcohols followed by carbonylation and quenching with iodine. The synthesis of (S)- (+)-5,6-2H-pyran-2-one (parasorbic acid)
- Dupont, Jairton,Donato, Augusto J.
-
p. 949 - 954
(2007/10/03)
-
- Preparation of lactones with several ring sizes via the same intermediate
-
Several lactones were prepared from (S)-1-(phenylsufonyl)-3-butanol 2 by cyclization of alkylation products of its silyl derivative 3 with electrophilic reagents bearing a functional group.
- Robin,Huet
-
p. 2945 - 2948
(2007/10/02)
-
- Asymmetric Hydrogenation of 3,5-Dioxoesters Catalyzed by Ru-binap Complex: A Short Step Asymmetric Synthesis of 6-Substituted 5,6-dihydro-2-pyrones
-
Asymmetric hydrogenation of 3,5-dioxoesters 1a-c using Ru2Cl4((R) or (S)-binap)2(NEt3) as the catalyst gave dominantly anti 3,5-dihydroxyesters 2, which were then converted into unsaturated lactones 5a-b (ca. 80percent e.e.).The pathway of the hydrogenation reaction was also investigated by asymmetric hydrogenation of (R)- or (S)-5-hydroxy-3-oxoesters 8a-c.It was revealed that the Ru-binap catalyzed hydrogenation of 1a-b proceed dominantly via the β-diketone mode.A convenient asymmetric synthesis of hydroxylactone 3c and unsaturated lactone 5c was presented.Key words: 3,5-dioxoester; Ru-binap catalyst; asymmetric hydrogenation; asymmetric synthesis; lactone
- Shao, Liming,Kawano, Hiroyuki,Saburi, Masahiko,Uchida, Yasuzo
-
p. 1997 - 2010
(2007/10/02)
-
- SYNTHESIS OF ENANTIOMERICALLY PURE (S)-5,6-DIHYDRO- AND (S)-TETRAHYDRO-6-METHYL-2H-PYRAN-2-ONE
-
An efficient synthesis of enantiomerically pure (S)-5,6-dihydro-6-methyl-2H-pyran-2-one, 6, and (S)-tetrahydro-6-methyl-2H-pyran-2-one, 7, from (S)-1-(1,3-dithian-2-yl)-2-hydroxypropane, is reported.
- Bernardi, Rosanna,Ghiringhelli, Dario
-
p. 395 - 396
(2007/10/02)
-
- Methyl (3R)-3-Hydroxyhex-5-enoate as a Precursor to Chiral Mevinic Acid Analogues
-
Baker's yeast reduction of methyl 3-oxohex-5-enoate 14b provides methyl (3R)-3-hydroxyhex-5-enoate 15b with 78percent enantiomeric enrichment.Subsequent seleno- and iodo-lactonization of derived hex-5-enoic acids leads to valerolactones 18, 19, 25 and 26 which are suitable for the subsequent elaboration of a variety of mevinic acid analogues.The absolute configuration of the major enantiomer produced in the initial yeast reduction was determined by correlation with natural (S)-(+)-parasorbic acid 23.
- Bennett, Frank,Knight, David W.,Fenton, Garry
-
p. 133 - 140
(2007/10/02)
-
- Asymmetric Hydrogenation of Methyl 3,5-Dioxohexanoate Catalyzed by Ru-binap Complex: A Short Step Asymmetric Synthesis of Dihydro-6-methyl-2H-pyran-2-one
-
Hydrogenation of methyl 3,5-dioxohexanoate 3 using Ru2Cl4((R) or (S)-binap)2(NEt3) as the catalyst gave dominantly anti 3,5-dihydroxyester 9, which was then converted into unsaturated lactone 4.The pathway of the hydrogenation reaction was also investigated. Key words: β,δ-diketonester; Ru-binap catalyst; asymmetric hydrogenation; asymmetric synthesis; lactone.
- Shao, Liming,Seki, Toshiyuki,Kawano, Hiroyuki,Saburi, Masahiko
-
p. 7699 - 7702
(2007/10/02)
-
- Synthesis of 1,3-dioxin-4-ones having chiral hydroxyalkyl groups at the 6-position by means of baker's yeast reduction and their uses for epc synthesis
-
Prochiral methyl ketones connected with 6-(4-oxo-1,3-dioxinyl) group directly or through methylene chain (1-3) gave, by treatment with fermenting baker's yeast, the corresponding (S)-alcohols which served as synthons for a variety of enantiomerically pure
- Sakaki, Jun-Ichi,Sugita, Yoshiaki,Sato, Masayuki,Kaneko, Chikara
-
p. 6197 - 6214
(2007/10/02)
-
- Highly enantioselective reduction of acetoacetylated Meldrum's acid with fermenting baker's yeast
-
Acetoacetylated Meldrum's acid was enantioselectively reduced with fermenting baker's yeast to afford the corresponding chiral (S)-alcohol, which could be easily converted to δ-lactone derivatives.
- Sato,Sakaki,Sugita,Nakano,Kaneko
-
p. 7463 - 7466
(2007/10/02)
-
- Synthesis of (S)-(+)-parasorbic acid and (S)-(+)-2-tridecanol acetate: Bakers' yeast reductions of γ and δ ketosulfones
-
The enantioselective reduction of 4-(p-toluenesulfonyl) butane-2-one and 5-(p-toluenesulfonyl) pentane-2-one with bakers' yeast gave the corresponding (S) alcohols in high optical purities and moderately good yields. The alcohol 2a was converted to (S)(+)parasorbic acid (4), while 2b was used for the preparation of (S)(+)-2-tridecanol acetate (7), using short synthetic sequences.
- Gopalan, Aravamudan S.,Jacobs, Hollie K.
-
p. 5575 - 5578
(2007/10/02)
-
- CHIRAL SYNTHONS FOR THE ELABORATION OF MEVINIC ACID ANALOGUES
-
Baker's yeast reduction of methyl 3-oxo-5-hexenoate (6b) affords the (R)-hydroxy-ester (7b) (76percent ee) wich is converted into the lactones (15) and epoxy-ester (19), synthons of the lactone part of the mevinic acids.
- Bennett, Frank,Kinght, David W.,Fenton, Garry
-
p. 4865 - 4868
(2007/10/02)
-
- EPOXY-SILANES IN ORGANIC SYNTHESIS
-
Stereoselective reactions involving functionalised β,γ-epoxysilanes and epoxide-allylsilanes provide a range of synthetically useful transformations.
- Procter, Garry,Russell, Andrew T.,Murphy, Patrick J.,Tan, T.S.,Mather, Andrew N.
-
p. 3953 - 3974
(2007/10/02)
-