203244-94-4Relevant academic research and scientific papers
Bond rotation dynamics of enamides: The effect of the acyl group and potential for chirality transfer during 5-endo trig radical cyclizations
Clark, Andrew J.,Curran, Dennis P.,Geden, Joanna V.,James, Natalie,Wilson, Paul
, p. 4546 - 4551 (2011/07/31)
Barriers to rotation of the N-alkenyl bond in a series of N-cycloalkenyl-N-benzyl acetamide derivatives have been measured in different solvents by variable-temperature NMR experiments. The barriers range from 9.7 to 14.2 kcal/mol, depending on substituents on the acetamide acyl group. Polar solvents such as chloroform and methanol increase the barrier to rotation compared to nonpolar solvents such as toluene. The barrier to rotation of "mimics" for acetamide-based radicals are estimated. The relative order of the values of krot for different acyl groups parallels their reported Taft Es paramaters. For successful chirality transfer in 5-endo trig radical cyclization, it is evident that rotations would need to be significantly slower than those reported here.
Preparation of N-heterocycles by radical cyclisation of enamides mediated by manganese(III) or copper(I). A comparison of cyclisation methods
Davies, David T.,Kapur, Neha,Parsons, Andrew F.
, p. 3941 - 3949 (2007/10/03)
Reaction of enamides with manganese(III) acetate or copper(I) chloride/bipyridine has been investigated. In both cases, an initial 5-endo- trig radical cyclisation reaction took place to produce functionalised pyrrolidinones. The copper(I)-mediated cyclisations were very efficient and bicyclic dienes could be isolated in >80% yield, while the corresponding manganese(III) reactions were generally more problematic, giving related dienes in lower yield (35-52%). (C) 2000 Elsevier Science Ltd.
β- and γ-lactams by nickel powder mediated 4-exo or 5-endo radical cyclisations. A concise construction of the mesembrine skeleton
Cassayre, Jerome,Quiclet-Sire, Beatrice,Saunier, Jean-Baptiste,Zard, Samir Z.
, p. 1029 - 1040 (2007/10/03)
N-Alkenyl trichloroacetamides, upon treatment with nickel powder and acetic acid in refluxing 2-propanol undergo reversible 4-exo radical cyclisation. The cyclised radical can be trapped in different ways leading to β-lactams. When the trap is omitted or not efficient enough, unusual irreversible 5-endo cyclisation occurs affording functionalised five-membered lactams. Synthesis of bicyclic γ-lactams has also been examined providing in few steps an access to the Sceletium alkaloids skeleton.
