13672-25-8Relevant academic research and scientific papers
Generation of All-Carbon Quaternary Stereocenters at the C-3 Carbon of Lactams via [3,3]-Sigmatropic Rearrangement and Revision of Absolute Configuration: Total Synthesis of (-)-Physostigmine
Pandey, Ganesh,Khamrai, Jagadish,Mishra, Akash
supporting information, p. 166 - 169 (2018/01/17)
A diastereoselective (up to >99%) route to all carbon quaternary stereocenters at the C-3 position of cyclic lactams has been developed via Johnson-Claisen rearrangement of ?-hydroxy-α,β-unsaturated lactams. It has been observed that olefin geometry plays an important role in the development of the absolute stereochemistry of the product. Dependence of product configuration on the olefin geometry is explained by postulating probable transition states. The success of this method has been shown for multigram-scale synthesis of these substituted lactams from commercially available cheap starting materials. The synthetic usefulness of this method is also demonstrated by carrying out the total synthesis of (a-)-physostigmine.
RETRACTED ARTICLE: An expeditious route to both enantiomers of all carbon quaternary stereocenters at C-3 carbon of lactams via [3,3]-sigmatropic rearrangement: Total synthesis of (-)-physostigmine
Pandey, Ganesh,Khamrai, Jagadish,Mishra, Akash
supporting information, p. 952 - 955 (2015/04/27)
A diastereoselective route to all carbon quaternary stereocenters at the C-3 position of cyclic lactams has been developed via Johnson-Claisen rearrangement of γ-hydroxy-α, β-unsaturated lactams. It has been observed that olefin geometry plays an important role in the development of the absolute stereochemistry of the product. The dependence of the product configuration on the olefin geometry is explained by postulating probable transition states. The success of this method has been shown for the multigram scale synthesis of these substituted lactams from commercially available cheap starting materials. The synthetic usefulness of this method is also demonstrated by carrying out the total synthesis of (-)-physostigmine.
Chemoselective reduction of isatin-derived electron-deficient alkenes using alkylphosphanes as reduction reagents
Cao, Shu-Hua,Zhang, Xiu-Chun,Wei, Yin,Shi, Min
supporting information; experimental part, p. 2668 - 2672 (2011/06/25)
Under mild reaction conditions, the C=C double bond inisatin-derived electron-deficient alkenes has been exclusively reduced in the presence of alkylphosphanes and water to afford the corresponding reduction products in good to excellent yields. A plausib
Generation and cyclization of unsaturated carbamoyl radicals derived from S-4-pentynyl carbamothioates under tin-free conditions
Benati, Luisa,Bencivenni, Giorgio,Leardini, Rino,Minozzi, Matteo,Nanni, Daniele,Scialpi, Rosanna,Spagnolo, Piero,Zanardi, Giuseppe
, p. 3192 - 3197 (2007/10/03)
The radical reaction of benzenethiol with S-4-pentynyl carbamothioates provides a valuable protocol for the tin-free generation of carbamoyl radicals, which arise from intramolecular substitution at sulfur by the initial sulfanylvinyl radicals. This procedure can be usefully employed to achieve N-benzylcarbamoyl radical 5-exo and 4-exo cyclizations leading, respectively, to pyrrolidinones and azetidinones, although, for the latter, it seems of lesser utility. Novel evidence is presented that. N-tosyl-substituted carbamoyl radicals display a peculiar tendency to yield the corresponding isocyanate by β-elimination of the tosyl radical.
A lewis-acid catalyzed synthesis of substituted oxindole derivatives
Yamazaki, Shoko,Yamamoto, Machiko,Morikawa, Satoshi
, p. 269 - 289 (2007/10/03)
Lewis acid-catalyzed cyclization of various 2-(N-arylcarbamoyl)-methylenemalonates to give nitrogen-containing benzo-annelated heterocycles was investigated in terms of selectivity. Reaction of substrates with various alkyl groups on nitrogen proceeded to
