- A Total Synthesis of Salinosporamide A
-
Salinosporamide A is a β-lactone proteasome inhibitor currently in clinical trials for the treatment of multiple-myeloma. Herein we report a short synthesis of this small, highly functionalized, biologically important natural product that uses an oxidative radical cyclization as a key step and allows for the preparation of gram quantities of advanced synthetic intermediates.
- Marx, Léo B.,Burton, Jonathan W.
-
supporting information
p. 6747 - 6754
(2018/05/14)
-
- An improved synthesis of ethyl cis-5-iodo-trans-2-methylcyclohexanecarboxylate, a potent attractant for the Mediterranean fruit fly
-
Both racemic ethyl 5-iodo-2-methylcyclohexanecarboxylate (1), known as Mediterranean fruit fly attractant ceralure B1, and its (-)-(1R,2R,5R) enantiomer 1a were conveniently synthesized from commercially available racemic trans-6-methyl-3-cyclohexenecarboxylic acid 2 or its (1R,6R) enantiomer 2a. Key steps included an asymmetric Diels-Alder reaction using a sultam auxiliary and cyclization of the unwanted trans-5-iodo-trans-2-methylcyclohexanecarboxylic acid (8) to the intermediate lactone 7 (or 8a to 7a). The new method may circumvent chromatographic separations and seems amenable to scale-up.
- Khrimian, Ashot,Margaryan, Armenak Kh.,Schmidt, Walter F.
-
p. 5475 - 5480
(2007/10/03)
-
- Syntheses of isotopically labelled L-?±-amino acids with an asymmetric centre at C-3
-
Approaches are described to the synthesis of a series of isotopically labelled L-a-amino acids each with an asymmetric centre at C-3, including isoleucine, allo-isoleucine, threonine and allo-threonine. The methods may be simply adapted for the selective incorporation of an isotopic label at each site of L-valine including the selective labelling of either diastereotopic methyl group with carbon-13 and/or deuterium and labelling of the amine with nitrogen-15. ? The Royal Society of Chemistry 2000.
- Harding, John R.,Hughes, Rachael A.,Kelly, Nicholas M.,Sutherland, Andrew,Willis, Christine L.
-
p. 3406 - 3416
(2007/10/03)
-
- Progress toward the total synthesis of callipeltin A (I): Asymmetric synthesis of (3S,4R)-3,4-dimethylglutamine
-
(equation presented) During the total synthesis of the novel cyclic depsipeptide callipeltin A (1), the unit (3S,4R)-3,4-dimethylglutamine, was successfully synthesized by asymmetric Michael addition and subsequent electrophilic azidation. The key feature of this approach is the generation of three adjacent stereogenic centers using the same camphorsultam chiral auxiliary.
- Liang, Bo,Carroll, Patrick J.,Joullie, Madeleine M.
-
p. 4157 - 4160
(2007/10/03)
-
- Ruthenium catalyzed asymmetric dihydroxylation with sultams as chiral auxiliaries
-
Ruthenium catalyzed asymmetric dihydroxylations of α,β-unsaturated carbonyl compounds with sultams 4, 5 and 6 as chiral auxiliaries are reported.
- Lee, Albert W.M.,Chan,Yuen,Xia,Wong
-
p. 1421 - 1424
(2007/10/03)
-
- Stereoselectivity and Generality of the Palladium-Catalysed Cyclopropanation of α,β-Unsaturated Carboxylic Acids Derivatized with Oppolzer's Sultam
-
A series of α,β-unsaturated carboxylic acids derivatized with camphorsultam 1 a s a chiral auxiliary has been stereoselectively cyclopropanated. the selectivity of the reaction produces cyclopropanated products with the 1R,2R absolute configuration as indicated by the optical rotations as well as by an X-ray structure determineation.The temperature dependence of the reaction was studied with three substrates. the highest stereoselectivity was obtained at temperatures above 25 deg C.Branching at the α- or β-carbons disfavours complete conversion, and electron-withdrawing substituents at these positions seem to prevent the reaction.The auxiliary was removed by using titanium(IV) isopropoxide in benzyl alcohol followed by alkaline hydrolysis of the intermediate ester. the potent 5-HT1A receptor agonist (1R,2S)-2-(2-hydroxyphenyl)-N,N-dipropylcyclopropylamine 13 was synthesized by this method
- Vallaerda, Jerk,Appelberg, Ulf,Csoeregh, Ingeborg,Hacksell, Uli
-
p. 461 - 470
(2007/10/02)
-
- Asymmetric Dihydroxylations of β-Substituted N-(α,β-Enolyl)bornane-10,2-sultams
-
Pure (E)- or (Z)-enoylsultams 2 were oxidized with OsO4/N-methylmorpholine N-oxide in a stereospecific and highly ?-face selective manner.Acetalization of the resulting 1,2-diols furnished, after purification, the stable, crystalline acetals 6 in >99percent d.e. and in 63-74percent overall yield from 2.Reductive or hydrolytic cleavage of 6 gave enantiometrically pure alcohols 8 or carboxylic acids 9 with recovery of the sultam auxiliary 1.
- Oppolzer, Wolfgang,Barras, Jean-Pierre
-
p. 1666 - 1675
(2007/10/02)
-
- ASYMMETRIC INDUCTION AT C(β) AND C(α) OF N-ENOYL SULTAMS BY 1,4-HYDRIDE ADDITION/ENOLATE TRAPPING
-
Conjugate addition of L-Selectride to α,β-enoyl sultams 1 and 4 followed by electrophilic trapping of the resulting enolates gave in one operation saturated imides with high β- and/or α- stereodifferentiation.
- Oppolzer, Wolfgang,Poli, Giovanni
-
p. 4717 - 4720
(2007/10/02)
-
- Camphor-Derived N-Acryloyl and N-Crotonoyl Sultams: Practical Activated Dienophiles in Asymmetric Diels-Alder Reactions
-
Starting from (+)-camphor-10-sulfonyl chloride (5), the crystalline sultam 8 was easily prepared.Lewis-acid-promoted Diels-Alder additions of the crystalline N-acryloyl and N-crotonoyl derivatives 9 and 10, respectively, to cyclopentadiene and 1,3-butadiene at -130 to -78 grad furnished adducts 11, 12 and 17 with high chiral efficiency.Crystallization of the adducts and nondestructive removal of 8 gave either alcohols 13, 14 and 18 or acid 19 in 99percent enantiomeric purity.The sense of induction was reversed on using the enantiomer of 8 as the auxiliary.The structure of 10 was established by X-ray diffraction analysis
- Oppolzer, Wolfgang,Chapuis, Christian,Bernardinelli, Gerald
-
p. 1397 - 1401
(2007/10/02)
-
