A Practical One-Pot Transformation of Triphenylphosphine Oxide to Triphenylphosphine by Reduction of in situ Generated Triphenylphosphine Dichloride

Abstract

One-pot transformation of triphenylphosphine oxide to triphenylphosphine was achieved by the reaction of triphenylphosphine oxide with oxalyl chloride, which led to the formation of triphenylphosphine dichloride, and subsequent reduction of triphenylphosphine dichloride with a combination of aluminum-catalytic metal salt.

Rasta resin–triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions

“…From an atom economy perspective this is less than ideal, and from an environmental point of view it would be good if 1 could be simply reduced to triphenylphosphine ( 2 ) for reuse [4]. In this regard Tanaka and co-workers have studied the possibility of applying the reaction first reported by Masaki and Fukui [5] in which 1 can be treated with oxalyl chloride (or bromide) to form halophosphonium salt 3a (or 3b ), which in turn can be reduced to 2 under more mild reaction conditions than can 1 (Scheme 1) [6–7]. …”

Electrochemical Reduction of Quaternary Phosphonium Derivatives: A Systematic Optimization Approach

“…1−7,9−13 Alternatives to conventional reductions have gained increasing interest. 3,6,7,[9][10][11]13 In fact, one promising alternative is the electrochemical reduction of 1 to reduce P V to P ΙΙΙ , as shown in Scheme 1…”

“…Over the past decade, many scientists have focused their studies on the reduction of triphenylphosphine oxide ( 1 , TPPO) toward triphenylphosphine ( 2 , TPP). − TPPO is known to be chemically stable but economically undesirable due to its strong oxygen–phosphorus double bond (PO; 546 kJ/mol) . It is a waste product of the Wittig olefination reaction (WOR), which has been the most famous olefination reaction for decades due to its high E / Z selectivity.…”

“…One of the most prominent products of the WOR is the industrial synthesis of Vitamin A (BASF, Rhône-Poulenc, DSM) whose annual production has tripled over the past decade (2012, 2700 t/a; 2020, 7500 t/a). , It has remained indispensable in animal feedstock (∼70–80% of yearly production) due to an ever-increasing demand for meat but is also used as a coloring agent, food stabilizer, emulsifier, and vitamin supplement . The recycling of 2 from 1 has so far been conducted via sacrificial agents (silanes, boranes, and allanes). − ,− Alternatives to conventional reductions have gained increasing interest. ,,,− , In fact, one promising alternative is the electrochemical reduction of 1 to reduce P V to P ΙΙΙ , as shown in Scheme…”

Tertiary Amine-Mediated Reductions of Phosphine Oxides to Phosphines

“…Our original proposal was to replace elemental metal reductants , or silanes with alternative organic molecules or inorganic salts. We speculated that a potential candidate for the reductant should be an electron-rich molecule which favors a 1-electron or 2-electron transfer with the P(V) species.…”