Pyrolysis of β,γ,β′-trioxo phosphorus ylides: Convenient synthesis of symmetrical and unsymmetrical diacylalkynes

Methyl Chlorooxalate

“…In the first example below (eq 5), a phosphorous ylide is acylated and the product undergoes a thermal rearrangement to generate a diacyl acetylene product. 12 In another application (eq 6), dimethylcarbamoyl tetramethylsilane is acylated to generate a tricarbonyl product. 13 …”

Generation and Utilisation of P-cyclic α-methoxycarbonyl-methylenephosphoranes

“…2,3 A more general approach was described by Aitken and co-workers involving the acylation of phosphoranes by α-oxo-acid chlorides. [4][5][6][7] This route is of practical importance as the starting materials are easily available. 4,5 We wished to apply the acylation approach, to extend the scope of P-cyclic β-oxophosphoranes.…”

“…[4][5][6][7] This route is of practical importance as the starting materials are easily available. 4,5 We wished to apply the acylation approach, to extend the scope of P-cyclic β-oxophosphoranes. Note that the novel reaction described is suitable only for the preparation of phosphoranes with trialkylphenyl substituent on the phosphorus atom.…”

“…Aitken, moreover, utilised the β-oxophosphoranes in the synthesis of di-or monosubstituted acetylenes by flash vacuum pyrolysis. [4][5][6][7] Our approach applying the reaction of cyclic phosphine oxides and dialkyl acetylenedicarboxylates to furnish β-oxophosphoranes followed by deacylation 8 represents a retro synthetic route (Scheme 1).…”

Reactions of β-oxo-α,β-bis(alkoxycarbonyl)phosphonium ylides based on P-heterocycles

“…[1][2][3] It is also known that a variety of α-ketophosphoranes undergo thermolysis to form phosphine oxides and alkynes. [4][5][6][7][8] This transformation is just the reverse of the one involving the interaction of phosphine oxides 1a-c and DMAD to furnish product 2a-c.…”