917481-50-6Relevant articles and documents
3,5-Bis(trifluoromethyl)phenyl sulfones in the Julia-Kocienski olefination - Application to the synthesis of tri- and tetrasubstituted olefins
Alonso, Diego A.,Fuensanta, Monica,Najera, Carmen
, p. 4747 - 4754 (2006)
3,5-Bis(trifluoromethyl)phenyl (BTFP) sulfones 8a-d are successfully employed in the modified Julia olefination reaction with carbonyl compounds employing phosphazene base P4-tBu at room temp. in THF, affording tri- and tetrasubstituted olefins in good yi
Development of Palladium-Catalyzed Decarboxylative Allylation of Electron-Deficient Sulfones and Identification of Unusual Side Products
Gill, Monica A.,Manthorpe, Jeffrey M.
, p. 6028 - 6039 (2019/05/24)
The use of sulfones as electron-withdrawing groups in substrates for palladium-catalyzed decarboxylative allylation was explored. A previously published trifluoromethanesulfonyl-based substrate was highly reactive and selective under mild conditions, but the substrate scope was not readily expanded. Instead, 3,5-bis(trifluoromethyl)phenyl sulfones were employed, thereby simultaneously retaining most of the electron deficiency and providing facile synthetic access. Optimization of the catalytic conditions to maximize the product distribution to a synthetically useful level of the allylation product over the protonation side product proved extremely challenging, with inconsistent and irreproducible results afforded with Pd2(dba)3 as the palladium source. A variety of substrates were subjected to the optimized catalytic conditions of PdCp(1-cinnamyl) and Xantphos in tetrahydrofuran at 50 °C for 30 min. These conditions were applicable to all substrates with the exception of the α,α-dimethyl allyl ester, which required more forcing conditions and afforded four products: the allylation and protonation products, as expected, along with a cyclopropylation product and an unprecedented pseudodimeric product. The mechanism for the formation of these unusual side products is considered.
