ChemInform Abstract: Novel Base‐Free Catalytic Wittig Reaction for the Synthesis of Highly Functionalized Alkenes.

Abstract

This novel base‐free Wittig reaction uses a readily available phosphine oxide as precatalyst and trimethoxy silane as reducing agent.

Iterative Arylation of Itaconimides with Diazonium Salts through Electrophilic Palladium Catalysis: Divergent β-H-Elimination Pathways in Repetitive Matsuda–Heck Reactions

“…Although several modifications and improvements, including a catalytic variant, 18 have been published since the original report, 6,[19][20][21][22][23] some disadvantages of this approach remain: in general, elevated temperatures and protic solvents are required to achieve useful levels of conversion, which may affect hydrolytic stability of the succinimide structure; 24 the required benzaldehydes are sometimes prone to oxidation and need to be purified beforehand; other carbonyl groups that may also undergo Wittig olefination reactions are not tolerated; the inevitable formation of stoichiometric amounts of phosphine oxides can hamper product isolation and purification if the 3-arylmethylidene pyrrolidine-2,5-diones have similar polarity. In continuation of our previous investigations [25][26][27] into the development and application of Matsuda-Heck reactions, 28 i. e. the Pd-catalyzed Heck-type coupling of arene diazonium salts with alkenes, [29][30][31][32][33][34][35][36] we wondered whether an alternative approach to 3-arylmethylidene pyrrolidine-2,5-diones exo-1 that starts from itaconimides 5 and stable and isolable arene diazonium salts 6 might be a competitive or even advantageous alternative to the phospha-Michael-addition / Wittig-olefination approach.…”