Flash Vacuum Pyrolysis of Stabilised Phosphorus Ylides. Part 1. Preparation of Aliphatic and Therminal Alkynes
Thermal extrusion of Ph3PO from β-oxoalkylidenetriphenylphosphoranes 4 to give the alkynes 5, which under conventional pyrolysis conditions is restricted to cases in which R1 is an electron withdrawing group, has been successfully achieved for R1=H or alkyl by using FVP.The method allows convenient construction of multigram quantities of the alkynes 5 from alkyl halides 1 and allows convenient construction of multigram quantities of the alkynes 5 from alkyl halides 1 and acid chlorides 3 in three steps with good overall yields.Under the conditions used the ylides with R2 = cyclobutyl also undergo less of ethene to provide convenient access to the vinylalkynes 6.
Aitken, R. Alan,Atherton, J. Ian
p. 1281 - 1284
(2007/10/02)
A New General Synthesis of Aliphatic and Terminal Alkynes: Flash Vacuum Pyrolysis of β-Oxoalkylidenetriphenylphosphoranes
By using flash vacuum conditions the thermal elimination of Ph3PO from β-oxoalkylidenetriphenylphosphoranes, previously confined to cases with an α-electron withdrawing group, has been extended to provide a general, high yielding synthesis of aliphatic and terminal alkynes.
Aitken, R. Alan,Atherton, J. Ian
p. 1140 - 1141
(2007/10/02)
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