Stereoselective synthesis of cis and trans-fused 3a-aryloctahydroindoles using cyclization of N-vinylic α-(methylthio)acetamides: synthesis of (-)-mesembrane

金沢大学大学院自然科学研究科生理活性物質科学金沢大学薬学部Treatment of N-(2-arylcyclohex-1-en-1-yl)-α-(methylthio)acetamides with N-chlorosuccinimide (NCS) gave 3a-aryl-2,3,3a,4,5,6-hexahydro-3-(methylthio)indol-2-ones. Desulfurization of the cyclization products followed by a catalytic hydrogenation of the resulting hexahydroindol-2-ones gave predominantly or exclusively trans-fused octahydroindol-2-ones. On the other hand, reduction of the desulfurization products with Et3SiH in CF3CO2H exclusively provided cis-fused octahydroindol-2-ones. A chiral induction of N-[2-(3,4-dimethoxy)phenylcyclohex-1-en-1-yl]-α-(methylthio)acetamide having an (R)-1-(1-naphthyl)ethyl group on the nitrogen atom led to the synthesis of (-)-mesembrane and (-)-trans-mesembrane. © 2007 Elsevier Ltd. All rights reserved

One-pot oxidative carbon-carbon bond formation of 3-benzylic and 3-allylic indoles with carbon nucleophiles

金沢大学医薬保健研究域薬学系Indolenines were generated at -78 °C from 3-benzylic or 3-allylic indoles by dehydrogenation with N-tert-butylbenzenesulfinimidoyl chloride, and a carbon-carbon bond was formed at -78 °C in a one-pot manner by treating these indolenines with various carbon nucleophiles such as active methylene compounds or organocuprates. © 2008 Elsevier Ltd. All rights reserved

One-pot oxidative carbon-carbon bond formation of 3-benzylic and 3-allylic indoles with carbon nucleophiles

金沢大学医薬保健研究域薬学系Indolenines were generated at -78 °C from 3-benzylic or 3-allylic indoles by dehydrogenation with N-tert-butylbenzenesulfinimidoyl chloride, and a carbon-carbon bond was formed at -78 °C in a one-pot manner by treating these indolenines with various carbon nucleophiles such as active methylene compounds or organocuprates. © 2008 Elsevier Ltd. All rights reserved

One-pot carbon-carbon bond formation at the b-position of cyclic ketones: oxidative Michael addition with alkyl malonates

金沢大学大学院自然科学研究科生理活性物質科学金沢大学薬学部金沢大学医学部附属病院薬剤部A carbon-carbon bond was formed at the β-position of cyclic ketones in a one-pot manner by oxidation with N-tert-butylbenzenesulfinimidoyl chloride, followed by the reaction of malonic acid esters or potassium cyanide. © 2007 Elsevier Ltd. All rights reserved

Indium(III) triflate-catalyzed reaction of 2-carbomethoxycyclobutanone with nitrones

2-Carbomethoxycyclobutanone reacted with N-phenyl-C-arylnitrones to afford methyl 5-oxo-2-[aryl(phenylamino)methyl]tetrahydrofuran-2-carboxylates by the catalysis of indium(III) triflate in the presence of magnesium sulfate. © 2012 Elsevier Ltd. All rights reserved

Diels-Alder reaction of eight-membered cyclic siloxydienes

金沢大学医薬保健研究域薬学系Eight-membered cyclic siloxydienes, 2-(tert-butyldimethylsiloxy)-1-methyl-5-oxacycloocta-1,3-diene and 2-(tert-butyldimethylsiloxy)-5-oxacycloocta-1,3-diene, were prepared from δ-valerolactone, and their Diels-Alder reactions with various dienophiles are reported. © 2008 Elsevier Ltd. All rights reserved

Synthesis of 13a-methylphenanthroindolizidines using radical cascade cyclization: synthetic studies toward (±)-hypoestestatin 1

金沢大学大学院自然科学研究科生理活性物質科学A radical cascade involving 6-endo cyclization of aryl radicals generated from N-acryloyl-N-(1-methylethenyl)-9-bromophenanthren-10-ylmethylamines, followed by 5-endo-trig cyclization of the resulting α-amidoyl radicals afforded phenanthroindolizidines bearing a methyl substituent at the angular C13a position. 2,3,6-Trimethoxy derivative was synthesized by using this method, but its spectral data were not in accord with those of literature values reported for hypoestestatin 1. Further synthetic study toward hypoestestatin 1 is demonstrated. © 2007 Elsevier Ltd. All rights reserved

Stereoselective synthesis of trans-3a-aryloctahydroindoles using cyclization of N-vinylic α-(methylthio)acetamides

金沢大学大学院自然科学研究科生理活性物質科学金沢大学薬学部Treatment of N-(2-arylcyclohex-l-enyl)-α-(methylthio)acetamide with NCS underwent cyclization to give 3a-arylhexahydroindol-2-one, which was stereoselectively converted into trans-3a-aryloctahydroindole. © 2006 The Japan Institute of Heterocyclic Chemistry

Asymmetric reduction of aliphatic ketones and acyl silanes using chiral anti-pentane-2,4-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid

金沢大学医薬保健研究域薬学系Aliphatic ketones were reduced to the corresponding secondary alcohols by using anti-1,3-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid (DNBSA) in benzene at reflux. Addition of 1-octanethiol in that media improved the efficiency of the reduction. Asymmetric reduction of aliphatic ketones was performed by using chiral anti-pentane-2,4-diol, and highly asymmetric induction (up to >99% ee) was observed in the reduction of tert-alkyl ketones. Asymmetric reduction of acyl silanes using chiral anti-pentane-2,4-diol and DNBSA proceeded efficiently in the absence of octanethiol and the corresponding α-silyl alcohols were obtained in high yields with high ees. © 2010

Intramolecular formal [4+2] cycloaddition of 3-ethoxycyclobutanones and alkenes

金沢大学医薬保健研究域薬学系Intramolecular formal [4+2] cycloaddition between 3-ethoxycyclobutanones and a carbon-carbon double bond to the corresponding bicyclo[4.n.0]alkan-2-one derivatives proceeded effectively by using ethylaluminium dichloride. © The Royal Society of Chemistry 2010