6553-12-4Relevant articles and documents
Acyl Radicals: Intermolecular and Intramolecular Alkene Addition Reactions
Boger, Dale L.,Mathvink, Robert J.
, p. 1429 - 1443 (2007/10/02)
A full study of the use of phenyl selenoesters as precursors to acyl radicals and their subsequent participation in intermolecular and intramolecular alkene addition reactions is detailed.Primary alkyl-, vinyl-, and arylsubstituted acyl radicals generated by Bu3SnH treatment of the corresponding phenyl selenoesters participate cleanly in intermolecular addition reactions with alkenes bearing electron-withdrawing or radical-stabilizing substituents at rates that exceed those of the potentially competitive decarbonylation or reduction.Similarly, their intramolecular addition to activated or unactivated alkenes proceeds without significant competitive reduction or decarbonylation and at rates generally >/= 1 x 106 s-1 with some occuring at rates >/= 3 x 107 s-1.Consistent with their behavior in intermolecular addition reactions, the 5-exo-trig cyclizations of secondary and tertiary alkyl-substituted acyl radicals to an unactivated olefin acceptor may be accompanied by varying degrees of decarbonylation, even under low-temperature free-radical conditions.Studies are presented which suggest that the intramolecular additions of acyl radicals to alkenes under the conditions detailed herein may be regarded as irreversible, kinetically controlled processes which exhibit regioselectivity that is predictable based on well-established empirical rules set forth for the analogous free-radical cyclization reactions of alkyl radicals.
Acyl Radicals: Functionalized Free Radicals for Intramolecular Cyclization Reactions
Boger, Dale L.,Mathvink, Robert J.
, p. 3377 - 3379 (2007/10/02)
A study describing the use of phenyl selenoesters as direct precursors to acyl radicals suitable for the initiation of intramolecular free-radical cyclization reactions is detailed.
Pyrolysis of the Tosylhydrazone Sodium Salts of Two Bicyclic Lactones
Ayral-Kaloustian, Semiramis,Agosta, William C.
, p. 284 - 287 (2007/10/02)
Lactone tosylhydrazone sodium salt 17a was prepared from lactone 10 by way of thionolactone 14.The tert-butyl homologue 17b was available by way of hydroxy nitrile 5.Pyrolysis of these salts led to enol ethers 18a,b and the ring-contracted ketones 19a,b.Together with earlier work, our results suggest that biradical 3 is probably an intermediate in conversion of alkoxycarbene 2 to ketone 4 and that the activation energy for this biradical coupling is ca. 2-3 kcal/mol.
