1436596-49-4Relevant academic research and scientific papers
A novel sulfonamide non-classical carbenoid: A mechanistic study for the synthesis of enediynes
Hayes, Theodore O. P.,Slater, Ben,Horan, Richard A. J.,Radigois, Marc,Wilden, Jonathan D.
supporting information, p. 9895 - 9902 (2017/12/12)
Alkynyl sulfonamides undergo sequential 1,4- then 1,2-addition/rearrangement with lithium acetylides to yield enediynes in the absence of any promoters or catalysts. Mechanistic investigations suggest that the reaction proceeds via 1,4-conjugate addition of the nucleophile to the unsaturated system to give a key alkenyl lithium species which is stabilised by an intramolecular coordination effect by a sulfonamide oxygen atom. This species can be considered a vinylidene carbenoid given the carbon atom bears both an anion (as a vinyllithium) and a leaving group (the sulfonamide). The intramolecular coordination effect serves to stabilise the vinyllithium but activates the sulfonamide motif towards nucleophilic attack by a second mole of acetylide. The resulting species can then undergo rearrangement to yield the enediyne framework in a single operation with concomitant loss of aminosulfinate.
Transition-metal-free synthesis of aryl-substituted tert-butyl ynol ethers through addition/elimination substitution at an sp centre
Gray, Vincent J.,Slater, Ben,Wilden, Jonathan D.
supporting information, p. 15582 - 15585 (2013/01/16)
Nucleophilic attack of an alkoxide on an alkynyl sulfonamide leads to displacement of the sulfonamide at the sp centre and isolation of the ynol ether in good yield in a single operation (see scheme). The mechanistic pathway has been probed by the use of coordinating additives, 13C-labelling experiments and ab initio calculations, which indicated that an addition/elimination mechanism is in operation. Copyright
