Ethyl (2E,4Z)-5-diethyl­amino-2-(phenyl­sulfon­yl)penta-2,4-dienoate

In the title compound, C17H23NO4S, the penta­diene group adopts a planar conformation, with an r.m.s. deviation of 0.0410 (14) Å. The phenyl ring makes a dihedral angle of 85.73 (11)° with the penta­diene group, while the penta­diene group makes dihedral angles of 11.38 (11) and 14.08 (10)°, respectively, with the amino and ester groups. In the crystal, molecules are linked via pairs of C—H⋯O inter­actions, forming inversion dimers

Amide Activation by Tf2O: Reduction of Amides to Amines by NaBH4 under Mild Conditions

An expeditious and practical method for the reduction of amides to amines is reported. The method is consisted of activation of amides with Tf2O followed by reduction with sodium borohydride in THF at room temperature. Various amides/lactams gave the corresponding amines in good to excellent yields, even with hindered amides and secondary amides. This method also presents other advantages such as TBDPS-group tolerance, short reaction time, simple workup and purification procedure.NSF of China [20832005]; National Basic Research Program (973 Program) of China [2010CB833200

A new approach for the asymmetric syntheses of 2-epi-deoxoprosopinine and azasugar derivatives

A new approach to 2-epi-deoxoprosopinine 11, 1-deoxygulonojirimycin 7, and l-gulono-1,5-lactam 9 was described. The C-2 hydroxymethyl group was introduced regioselectively using SmI2 mediated coupling of (S)-3-silyloxyglutarimide 13b with either chloromethyl benzyl ether 16a or the Beau–Skrydstrup reagent 16b, followed by debenzylation and highly cis-diastereoselective reductive deoxygenation. Adoption of the Savoi's chemoselective ring-opening alkylation method allowed a highly diastereoselective introduction of the lipid side chain of 2-epi-deoxoprosopinine 11 in a straightforward manner. Dehydration followed by highly trans-diastereoselective dihydroxylation led to polyoxygenated lactam derivative 27 as a key intermediate for the syntheses of 7 and 9.the NSF of China (20272048; 203900505) and the Ministry of Education (Key Project 104201)

Versatile and chemoselective transformation of aliphatic and aromatic secondary amides to nitriles

通讯作者地址: Huang, PQTriflic anhydride in combination with 2-fluoropyridine effectively dehydrates secondary amides to afford nitriles under mild reaction conditions. The reaction is general in scope and compatible with the use of aliphatic, alpha,beta-unsaturated, aromatic, and heteroaromatic amides bearing either secondary, tertiary, or benzylic N-alkyl groups. The reaction also shows good to excellent chemoselectivity for the secondary amide and tolerates several labile functional groups.Natural Science Foundation of China (NSFC) 21332007 Program for Changjiang Scholars and Innovative Research Team in University of the Ministry of Education of Chin

First asymmetric synthesis of piperidine alkaloid (-)-morusimic acid D

The first asymmetric synthesis of (-)-morusimic acid D, a 2,3-trans-2,6-cis-2-methyl-6-substituted piperidin-3-ol containing alkaloid is reported. The key steps are the reductive alkylation of N,O-diprotected 3-hydroxyglutarimide, a stepwise reductive alkylation, and an asymmetric aldol-type reaction using a modified Evans chiral auxiliary

Studies towards the Total Asymmetric Synthesis of the Pentacyclic Indole Alkaloid Arboflorine: Asymmetric Synthesis of a Key Intermediate

The synthesis of a plausible key intermediate for a biomimetic asymmetric synthesis of indole alkaloid arboflorine is described. The method featured the use of Ellman's sulfinamide chemistry for the establishment of the first chiral center, and the Polonovski-Potier reaction for the formation of the alpha-aminonitrile moiety.NSF of China[20832005]; NFFTBS[J1030415]; National Basic Research Program (973 Program) of China[2010CB833200

A concise and fully selective synthesis of the ant venom alkaloid (3S,5R,8S,9S)-3-butyl-5-propyl-8-hydroxyindolizidine

A seven-step synthesis of (3S,5R,8S,9S)-3-butyl-5-propyl-8-hydroxyindolizidine (2), an ant venom alkaloid isolated from Myrmicaria melanogaster, is disclosed with an overall yield of 28.9%. The key feature of the synthesis is the use of the iodocyclization for the introduction of the hydroxyl group of the 3-piperidinol. Remarkably, all the reaction steps proceeded with excellent chemo-, regio- and/or diastereoselectivities.NSF of China [20832005]; National Basic Research Program (973 Program) of China [2010CB833206

A flexible carbanionic approach to protected trans-(2R,3S)-2-substituted 3-aminopyrrolidines: application to the asymmetric synthesis of (+)-absouline

Based on the use of phenyl thioether (3S)-7 as a synthetic equivalent to the N- and alpha-dianions (3S)-2a, a new carbanionic approach to trans-(2R,3S)-2-substituted 3-aminopyrrolidines (10) is described. Application of the method to the asymmetric synthesis of 1-aminopyrrolizidine alkaloid (+)-absouline is also reported

Efficient and chemoselective alkylation of amines/amino acids using alcohols as alkylating reagents under mild conditions

We report a mild and environmentally benign method for the synthesis of tertiary amines using alcohols as the alkylating reagents. Not only secondary amines such as piperazines but also amino acids and amino alcohols can be N-alkylated selectively. For N,O-benzyl protected amino alcohols, both N,O-de-benzylation and N-methylation were achieved in one-pot.NSF of China [20832005]; National Basic Research Program (973 Program) of China [2010CB833200