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1-Phosphaallenes AI simulator
(@1-Phosphaallenes_simulator)
Hub AI
1-Phosphaallenes AI simulator
(@1-Phosphaallenes_simulator)
1-Phosphaallenes
1-Phosphaallenes are allenes in which the first carbon atom is replaced by phosphorus, resulting in the structure: -P=C=C<.
The first example of a stable heteroalkene E=C or E=E' (E, E' = P) containing a heavy group 15 element was reported in 1982 by Yoshifuji. After the realization of heavier heteroalkenes, the field of organometallic chemistry began exploring the idea of heteroallenes E=C=E' and E=C=C=E', in which one or more carbon atom of an allene is substituted by a heavier atom. The first of these heteroallenes containing a heavier group 15 element to be reported was synthesized in 1984 by Yoshifuji. 1-phosphaallene, also referred to as ethenylidenephosphine or λ3-phosphaallene, was first synthesized using the 2,4,6-tri-t-butylphenyl (supermesityl, or Mes*) moiety as a sterically protecting group. The most widely known example of 1-phosphaalenes is the Mes* substituted 3H-phosphallene, where a hydrogen is bonded to the terminal carbon atom, which was synthesized by Märkl and Reitinger in 1988. Some more recent advances made in regards to 1-phosphaallenes include the development of simpler synthetic routes and the discovery of synthetic pathways using phosphaallenes to create molecules that are typically only synthesized through complicated methods.
Multiple synthetic routes to 1-phosphaallenes have been reported. The most common are Phospha-Wittig-Horner reactions, rearrangement of alkylynlphosphines with a base present, dehydrochlorination of a chlorovinylphospine, and the reaction of lithium with a C,C-dichlorophosphirane. More recent synthetic advances include the dehydrobromination of phosphaalkenes the hydroalumination of alkynylphosphines.
The Phospha-Wittig-Horner reaction, first reported by Mathey et al. in 1992, was initially developed as a synthetic route to convert aldehydes and ketones into C-mono and C,C-disubstituted phosphaalkenes, respectively. This method was then adapted to rapidly synthesize phosphaallenes by reacting phosphaketenes with an organolithium base, such as lithium diisopropylamide or t-BuOLi.
Like the transition from an alkyne to an allene in organic chemistry, phosphaallenes can be synthesized from alkynylphosphines by adding a strong base such as n-butyllithium (n-BuLi). These complexes are typically useful due to the broad range of stable products that can be obtained from this synthetic route.
Multiple stable phosphaallenes have been synthesized from LiC≡CR and ArP(H)Cl (R = Ph, t-Bu, Me, CH2OSiMe3). The basicity of the lithium complex is essential to the success of these reactions.
The dehydrochlorination of 1-chlorovinylphosphine by DBU (1,8-diazabicyclo-[5.4.0]undec-7-ene) yields a variety of results, depending on the structure of the initial chlorovinylphosphine. Many of these reactions require temperatures between −90 °C and 0 °C to ensure a stable product is formed. As many of these reactions are warmed, oligomerization of the phosphaallene occurs. Other reactions following this synthetic route occur with gas phase reagents at 250 °C.
In this synthetic route, a dichlorocarbene is first reacted with a phosphaethylene. The addition of t-BuLi to the resulting 2,2-dichlorophosphirane yields the phosphaallene. This route includes an insertion of carbon into the P=C bond of a phosphaalkene.
1-Phosphaallenes
1-Phosphaallenes are allenes in which the first carbon atom is replaced by phosphorus, resulting in the structure: -P=C=C<.
The first example of a stable heteroalkene E=C or E=E' (E, E' = P) containing a heavy group 15 element was reported in 1982 by Yoshifuji. After the realization of heavier heteroalkenes, the field of organometallic chemistry began exploring the idea of heteroallenes E=C=E' and E=C=C=E', in which one or more carbon atom of an allene is substituted by a heavier atom. The first of these heteroallenes containing a heavier group 15 element to be reported was synthesized in 1984 by Yoshifuji. 1-phosphaallene, also referred to as ethenylidenephosphine or λ3-phosphaallene, was first synthesized using the 2,4,6-tri-t-butylphenyl (supermesityl, or Mes*) moiety as a sterically protecting group. The most widely known example of 1-phosphaalenes is the Mes* substituted 3H-phosphallene, where a hydrogen is bonded to the terminal carbon atom, which was synthesized by Märkl and Reitinger in 1988. Some more recent advances made in regards to 1-phosphaallenes include the development of simpler synthetic routes and the discovery of synthetic pathways using phosphaallenes to create molecules that are typically only synthesized through complicated methods.
Multiple synthetic routes to 1-phosphaallenes have been reported. The most common are Phospha-Wittig-Horner reactions, rearrangement of alkylynlphosphines with a base present, dehydrochlorination of a chlorovinylphospine, and the reaction of lithium with a C,C-dichlorophosphirane. More recent synthetic advances include the dehydrobromination of phosphaalkenes the hydroalumination of alkynylphosphines.
The Phospha-Wittig-Horner reaction, first reported by Mathey et al. in 1992, was initially developed as a synthetic route to convert aldehydes and ketones into C-mono and C,C-disubstituted phosphaalkenes, respectively. This method was then adapted to rapidly synthesize phosphaallenes by reacting phosphaketenes with an organolithium base, such as lithium diisopropylamide or t-BuOLi.
Like the transition from an alkyne to an allene in organic chemistry, phosphaallenes can be synthesized from alkynylphosphines by adding a strong base such as n-butyllithium (n-BuLi). These complexes are typically useful due to the broad range of stable products that can be obtained from this synthetic route.
Multiple stable phosphaallenes have been synthesized from LiC≡CR and ArP(H)Cl (R = Ph, t-Bu, Me, CH2OSiMe3). The basicity of the lithium complex is essential to the success of these reactions.
The dehydrochlorination of 1-chlorovinylphosphine by DBU (1,8-diazabicyclo-[5.4.0]undec-7-ene) yields a variety of results, depending on the structure of the initial chlorovinylphosphine. Many of these reactions require temperatures between −90 °C and 0 °C to ensure a stable product is formed. As many of these reactions are warmed, oligomerization of the phosphaallene occurs. Other reactions following this synthetic route occur with gas phase reagents at 250 °C.
In this synthetic route, a dichlorocarbene is first reacted with a phosphaethylene. The addition of t-BuLi to the resulting 2,2-dichlorophosphirane yields the phosphaallene. This route includes an insertion of carbon into the P=C bond of a phosphaalkene.