3447-09-4Relevant academic research and scientific papers
Chemoselective reductive alkynylation of tertiary amides by Ir and Cu(i) bis-metal sequential catalysis
Huang, Pei-Qiang,Ou, Wei,Han, Feng
supporting information, p. 11967 - 11970 (2016/10/09)
We report herein a convenient and versatile method for the direct reductive alkynylation of tertiary amides to give propargylic amines through sequential Ir-catalysed hydrosilylation-Cu(i)-catalysed alkynylation. The reactions proceed chemoselectively at the amide group in the presence of several sensitive functional groups including the very reactive aldehyde group on either the amide or the alkyne coupling partner. The method is general for tert-amides with or without α-hydrogen.
A direct and general method for the reductive alkylation of tertiary lactams/amides: Application to the step economical synthesis of alkaloid (-)-morusimic acid D
Xiao, Kai-Jiong,Wang, Yu,Huang, Ying-Hong,Wang, Xiao-Gang,Huang, Pei-Qiang
, p. 8305 - 8311 (2013/09/24)
Full details of the direct and general method for the reductive alkylation of tertiary lactams and amides to give tertiary sec-alkylamines are presented. This one-pot method consists of in situ activation of a lactam or an amide with Tf2O/DTBMP, addition of a Grignard reagent, and reduction of the resulting iminium intermediates. Alkyl, benzyl, and aryl Grignard reagents and several reductants or reducing conditions (LiAlH4, NaBH4, Hantzsch ester, Bu3SnH, Pd(OH)2/C, H2) could be used effectively. Reductive alkylations of substituted lactams demonstrated good to excellent 1,3-asymmetric induction to provide the corresponding di- or trisubstituted pyrrolidine/piperidine in 6:1 (LiAlH4), 11:1 (Et 3SiH), and 20:1 (catalytic hydrogenation) cis/trans diastereoselectivity, respectively. The versatility of this methodology was demonstrated by its application in the concise stereoselective synthesis of piperidine alkaloid (-)-morusimic acid.
Versatile one-pot reductive alkylation of lactams/amides via amide activation: Application to the concise syntheses of bioactive alkaloids (±)-bgugaine, (±)-coniine, (+)-preussin, and (-)-cassine
Xiao, Kai-Jiong,Wang, Yu,Ye, Ke-Yin,Huang, Pei-Qiang
supporting information; experimental part, p. 12792 - 12796 (2011/02/22)
Direct entry: One-pot reductive alkylation of lactams/amides with Grignard reagents has been realized via lactam/amide activation with Tf2O. This method opens a direct entry to α-alkylated amines. The versatility of the method is illustrated by the concise syntheses of bioactive alkaloids (±)-bgugaine, (±)-coniine, (+)-preussin, and (?)-cassine.
Novel synthesis of substituted pyrrolidines and piperidines via radical addition-ionic cyclization reaction of oxime ethers
Miyata, Okiko,Takahashi, Shinya,Tamura, Akira,Ueda, Masafumi,Naito, Takeaki
, p. 1270 - 1284 (2008/09/17)
We have developed a novel synthetic route to nitrogen-containing heterocycles via radical addition-ionic cyclization reaction. Treatment of oxime ethers carrying the tosyloxy group with Et3B and alkyl iodide in the presence of Lewis acid gave the substituted pyrrolidines and piperidines. The reaction of oxime ethers carrying the methoxycarbonyl group proceeded under the same conditions to give the amino esters, which were easily converted into the corresponding lactams by the treatment with concd HCl. On the other hand, the oxime ether bearing the phenoxycarbonyl group afforded directly alkylated lactams under the radical reaction conditions. The utility of this domino reaction was demonstrated by the synthesis of (±)-bgugaine and the formal synthesis of 5,8-disubstituted indolizidine alkaloids.
