New Access to Trisubstituted 3-Pyrrolines under Phosphine Catalysis

Abstract

Conjugated dienes, properly activated by electron-withdrawing groups on both ends, are shown to be suitable substrates for phosphine-promoted organocatalytic processes. Their reactions with imines, under phosphine catalysis, afford a new and efficient synthetic approach to functionalized 3-pyrrolines.

Advances in nucleophilic phosphine catalysis of alkenes, allenes, alkynes, and MBHADs

“…9 The proposed mechanism begins as an aza-MBH reaction, with the phosphine adding across the activated alkene to form the phosphonium enoate 7 (Scheme 6). In the presence of the tosylimine 8 , aza-MBH occurs, followed by Michael addition, giving the intermediate 9 .…”

An Easy, Stereoselective Synthesis of Hexahydroisoindol‐4‐ones under Phosphine Catalysis

“…The method has been unexpectedly brought to light while expanding the scope of the recently disclosed reaction between electron-poor conjugated dienes and imines, under phosphine catalysis, shown in Scheme 2. [7] In this reaction, starting from acyclic conjugated dienes properly activated by electron-withdrawing groups on both ends, 3-pyrrolines were produced. [8] The cyclization took place selectively on the double bond substituted by the ester function, according to the formal activation of this bond by the nucleophilic phosphine.…”

Pericyclic Reaction of a Zwitterionic Salt of an Enedione-diazoester. A Novel Strategy for the Synthesis of Highly Functionalized Resorcinols

“…In examining the breadth of the Mukaiyama-Michael transformation of 1 and its applications, we employed trans -4-methoxy-3-buten-2-one ( 2 ) as the substrate with the expectation that an enolizable enedione6 would be formed whose chemistry could lead us to cycloaddition products that contained the diazoester functionality. As anticipated, the direct Mukaiyama-Michael product ( 3 ) was unstable, undergoing elimination under the reaction conditions to form α,β-unsaturated ketone 4 exclusively (Scheme 2),7 but the resulting enedione underwent an unexpected transformation resulting in the formation of a substituted resorcinol.…”