The SmI(2)-mediated cross-coupling of nitrones with β-silyl-α,β-unsaturated esters, followed by zinc reduction, allows an efficient and highly diastereoselective preparation of β-silyl lactams, which are precursors of β-hydroxy lactams through Tamao-Fleming oxidation. By applying the method to a cyclic, carbohydrate-derived nitrone, a new synthesis of (+)-australine has been realized in only 11 steps and in 21% overall yield from L-xylose.
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http://dx.doi.org/10.1021/ol203396s | DOI Listing |
Beilstein J Org Chem
December 2015
Institute of Organic Chemistry, TU Braunschweig, Hagenring 30, 38106 Braunschweig, Germany, .
The synthesis and reactivity of indole derivatives substituted in the benzene section was studied. Starting materials 4- and 6-iodoindole were conveniently prepared via the Batcho-Leimgruber route and purified by sublimation. Novel vicinally indolyl-substituted cyclopentanols with unexpected cis-configuration were formed by SmI2-mediated reductive dimerization of a 4-(indol-6-yl)butenone, obtained by Heck reaction.
View Article and Find Full Text PDFActa Crystallogr Sect E Struct Rep Online
April 2014
The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, People's Republic of China.
The title compound, C32H35NO4, is an unexpected product obtained in the SmI2-mediated radical cross-coupling of a lactam 2-pyridyl sulfone with an arone. The asymmetric unit contains two mol-ecules. In both mol-ecules, the core pyrrolidinone ring adopts an approximate envelope conformation (with the C atom bearling the benzyloxy substituent as the flap) and the cyclo-hexyl ring has a chair conformation.
View Article and Find Full Text PDFJ Org Chem
June 2014
Department of Chemistry, Faculty and Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
Stereoselective synthesis of the C'D'E'F' ring system of maitotoxin was achieved starting from the E' ring through successive formation of the D' and C' rings based on SmI2-mediated reductive cyclization. Construction of the F' ring was accomplished via Suzuki-Miyaura cross-coupling with a side chain fragment and Pd(II)-catalyzed cyclization of an allylic alcohol. The C'D'E'F' ring system inhibited maitotoxin-induced Ca(2+) influx in rat glioma C6 cells with an IC50 value of 59 μM.
View Article and Find Full Text PDFJ Org Chem
March 2013
Department of Chemistry and Fujian Provincial Key Laboratory of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, PR China.
We report, for the first time, the synthesis of 8-aza-analogues of PGE2. The SmI2-mediated cross coupling reactions of γ-lactam-hemiaminal 9, lactam 2-pyridyl sulfide 17, and lactam 2-pyridyl sulfone 18 with activated alkenes/alkyne were first developed, giving the corresponding γ-lactams in 49-78%, 45-75%, and 75-90%, respectively. The reactions of lactam 2-pyridyl sulfide and 2-pyridyl sulfone proceeded with ≥12:1 trans-diastereoselectivities.
View Article and Find Full Text PDFOrg Lett
February 2012
Département de Chimie Moléculaire (SERCO) UMR-5250, ICMG FR-2607, CNRS, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 09, France.
The SmI(2)-mediated cross-coupling of nitrones with β-silyl-α,β-unsaturated esters, followed by zinc reduction, allows an efficient and highly diastereoselective preparation of β-silyl lactams, which are precursors of β-hydroxy lactams through Tamao-Fleming oxidation. By applying the method to a cyclic, carbohydrate-derived nitrone, a new synthesis of (+)-australine has been realized in only 11 steps and in 21% overall yield from L-xylose.
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