316363-67-4Relevant articles and documents
Selective 7- endo -Cyclization of 3-Aza-5-alkenols through Oxidative Pd(II)-Catalyzed Olefin Oxyarylation
Gazzola, Silvia,Beccalli, Egle M.,Borelli, Tea,Castellano, Carlo,Diamante, Daria,Broggini, Gianluigi
, p. 503 - 508 (2018)
3-Aza-5-alkenols undergo selective 7- endo - trig cyclization when treated with a catalytic Pd(II) species, CuCl 2 and ArSnBu 3 giving 7-aryl-substituted oxazepanes. The intramolecular alkoxylation occurs with formation of a seven-me
Synthesis of 2,4-disubstituted piperidines via radical cyclization: Unexpected enhancement in diastereoselectivity with tris(trimethylsilyl)silane
Gandon, Lucile A.,Russell, Alexander G.,Gueveli, Tatyana,Brodwolf, Angela E.,Kariuki, Benson M.,Spencer, Neil,Snaith, John S.
, p. 5198 - 5207 (2007/10/03)
A novel approach to 2,4-disubstituted piperidines is reported, involving the radical cyclization of 7-substituted-6-aza-8-bromooct-2-enoates. Cyclization with tributyltin hydride affords the trans piperidines with trans/cis diastereomeric ratios ranging typically from 3:1 to 6:1. Cyclization with tris(trimethylsilyl)silane affords the same products with diastereomeric ratios of up to 99:1 in certain cases. The enhancement in diastereoselectivity results from the selective rearrangement of the minor stereoisomer through a cascade process involving radical cyclization to the piperidine radical, 1,5-radical translocation, and attack of the translocated radical onto the sulfonamide with extrusion of SO2 in a Smiles-type rearrangement. Slower trapping of the piperidine radical by tris(trimethylsilyl)silane compared to tributyltin hydride accounts for the occurrence of the rearrangement cascade in the former case.
