Intramolecular Activation of Enones by Electrophilic Phosphinidene Complexes to Construct 2-Phosphafurans

Abstract

Herein, we report a facile and highly atom-economic approach to 2-phosphafurans by using simple 2-chloroethylphosphine and acetylenic ketones. The key step of this protocol utilizes the Lewis acidity of electrophilic phosphinidenes to induce an intramolecular cyclization with enones. Dearomative hetero-Diels− Alder reactions of 2-phosphafurans provide two series of bicyclic phosphacycles. This rare synthetic application of Lewis acidity of electrophilic phosphinidene complexes represents a new frontier of phosphinidene chemistry.

Towards tetrasubstituted furans through rearrangement and cyclodimerization of acetylenic ketones

“…10 Very recently, our group disclosed an atom-economical approach to 2-phosphafurans by using simple 2-chloroethylphosphane and acetylenic ketones (Scheme 1c). 11…”

“…10 Very recently, our group disclosed an atom-economical approach to 2-phosphafurans by using simple 2-chloroethylphosphane and acetylenic ketones (Scheme 1c). 11 The classical synthetic techniques for C-P bond formation have mainly depended on phosphorus halides and their derivatives. In continuation of our research on synthetic application of phosphanes, we report herein the diphenylphosphane borane complex-facilitated cyclodimerization of acetylenic ketones, enabling efficient access to tetrasubstituted furans (Scheme 1d).…”

Phosphorus-Involved Wagner–Meerwein Rearrangement of Phosphiranes: An Entry to Four-Membered Phosphacycles

“…Previous research on the chemistry of low-coordinate organophosphorus species has shown how these types of phosphorus compounds can behave like their carbon analogy . The phosphorus–carbon analogy is dominated by the similar reactivity of PC and CC bonds, as well as phosphinidene complexes (RP → MLn) and carbenes . The fascinating low-coordinate phosphorus chemistry has produced a range of efficient new synthetic tools for building organophosphorus compounds.…”