4545-20-4Relevant articles and documents
Diversity-Orientated Stereoselective Synthesis through Pd-Catalyzed Switchable Decarboxylative C?N/C?S Bond Formation in Allylic Surrogates
Deng, Lei,Kleij, Arjan W.,Yang, Weibo
, p. 19156 - 19161 (2018/11/30)
Switchable catalytic transformation of reactants can be a powerful approach towards diversity-orientated synthesis from easily available molecular synthons. Herein, an endogenous ligand-controlled, Pd-catalyzed allylic substitution allowing for either selective C?N or C?S bond formation using vinylethylene carbonates (VECs) and N-sulfonylhydrazones as coupling partners has been developed. This versatile methodology provides a facile, divergent route for the highly chemo- and stereoselective synthesis of functional allylic sulfones or sulfonohydrazides. The newly developed protocol features wide substrate scope (nearly 80 examples), broad functional group tolerance, and potential for the late-stage functionalization of bioactive compounds. The isolation and crystallographic analysis of a catalytically competent π-allyl Pd complex suggests that the pathway leading to the allylic products proceeds through a different manifold as previously proposed for the functionalization of VECs with nucleophiles.
Tetraethylammonium bromide catalysed phase transfer reaction of potassium superoxide with hydrazones and tosylhydrazones
Kumar,Singh
, p. 579 - 583 (2007/10/03)
A variety of hydrazones and tosylhydrazones of carbonyl compounds have been investigated under the mild reaction conditions of potassium superoxide and tetraethylammonium bromide in dry dimethylformamide. As a result, hydrazones are generally transformed to their corresponding azines whereas tosylhydrazones undergo facile fragmentation to give the olefinic products in fairly good yields. The study highlights the use of tetraethylammonium bromide as an efficient and inexpensive catalyst for superoxide studies.
Reactions of [1.1.1]propellane
Wiberg, Kenneth B.,Waddell, Sherman T.
, p. 2194 - 2216 (2007/10/02)
The free radical addition reactions of [1.1.1]propellane (1) are described in some detail and allowed the preparation of a wide variety of 1,3-disubstituted bicyclo[1.1.1]pentanes. The reaction of 1 with free radicals was more rapid than that of bicyclo[1.1.0]butane (2), whereas bicyclo[2.1.0]pentane (3) was relatively inert. In some cases the free-radical additions led to oligomers, and in the case of tetrahydrofuran addition the chain-transfer constant was measured. The addition of thiophenol to 1 followed by reduction with the lithium radical anion from 4,4′-di-tert-butylbiphenyl gave 1-lithiobicyclo[1.1.1]petane, from which a variety of 1-substituted bicyclo[1.1.1]pentanes may be prepared. In the Baeyer-Villiger oxidation of 1-benzoylbicyclo[1.1.1]pentane, the terf-butyl group migrated in preference to the bicyclopentyl group. Conversion of the ketone to the tosylhydrazone followed by base treatment gave products of the type expected from the corresponding carbene. The reaction of 1 with NO in carbon disulfide gave a unique reaction in which nitro and thiocyano groups were introduced. The reactions of 1, 2, and 3 with NO2 also were examined. Whereas 1 gave 1,3-dinitrobicyclo[1.1.1]pentane, the other hydrocarbons followed different reaction paths. The reaction of 1 with electron-deficient alkenes and alkynes are described in some detail and are compared with the corresponding reactions of 2 and 3. Here, the relative reactivities of 1 and 2 were often comparable but varied considerably with the reagent used. Again, 3 was relatively unreactive. The reaction of 1 with Rh(I) gave a dimer, and evidence is presented for a metallocarbene intermediate.
