Acyl cyanide Synthesis
Classically acyl cyanides are produced by the salt metathesis reaction of acyl chlorides with sodium cyanide :
R
−
C
(
O
)
Cl
+
Na
CN
⟶
R
−
C
(
O
)
CN
+
NaCl
{\displaystyle {\color {red}{\ce {R-C(O)}}}{\ce {Cl}}+{\ce {Na}}{\color {red}{\ce {CN}}}\longrightarrow {\color {red}{\ce {R-C(O)CN}}}+{\ce {NaCl}}}
Alternatively, they can be produced by dehydration of acyl aldoximes :
R
−
C
(
O
)
C
H
=
N
OH
⟶
R
−
C
(
O
)
CN
+
H
2
O
{\displaystyle {\color {red}{\ce {R-C(O)C}}}{\ce {H=}}{\color {red}{\ce {N}}}{\ce {OH}}\longrightarrow {\color {red}{\ce {R-C(O)CN}}}+{\ce {H2O}}}
Acetyl cyanide is also prepared by hydrocyanation of ketene :
CH
2
=
C
=
O
+
H
CN
⟶
H
3
C
−
C
(
O
)
CN
{\displaystyle {\ce {CH2=}}{\color {red}{\ce {C=O}}}+{\ce {H}}{\color {red}{\ce {CN}}}\longrightarrow {\ce {H3C -}}{\color {red}{\ce {C(O)CN}}}}
Reactions
They are mild acylating agents.[ 2] carboxylate :[ 3]
R
−
C
(
O
)
CN
+
2
NaOH
⟶
R
−
CO
Na
2
+
Na
CN
+
H
2
O
{\displaystyle {\color {red}{\ce {R-C(O)CN}}}+{\ce {2 NaOH}}\longrightarrow {\color {red}{\ce {R-CO}}}{\ce {_2Na}}+{\ce {Na}}{\color {red}{\ce {CN}}}+{\ce {H2O}}}
With azides , acyl cyanides undergo the click reaction to give acyl tetrazoles .[ 4]
References
↑ Liu, Bing; Wang, Yong; Chen, Ying; Wu, Qian; Zhao, Jing; Sun, Jianwei (2018). "Stereoselective Synthesis of Fully-Substituted Acrylonitriles via Formal Acylcyanation of Electron-Rich Alkynes". Organic Letters . 20 (12): 3465– 3468. doi :10.1021/acs.orglett.8b01180 . PMID 29873500 . S2CID 46942109 . 1 2 Morris, Joel (2001). "Acetyl Cyanide". Encyclopedia of Reagents for Organic Synthesis . doi :10.1002/047084289X.ra026 . ISBN 0471936235 ↑ Hünig, Siegfried; Schaller, Rainer (1982). "The Chemistry of Acyl Cyanides". Angewandte Chemie International Edition in English . 21 : 36– 49. doi :10.1002/anie.198200361 . ↑ Demko, Zachary P.; Sharpless, K. Barry (2002). "A Click Chemistry Approach to Tetrazoles by Huisgen 1,3-Dipolar Cycloaddition: Synthesis of 5-Acyltetrazoles from Azides and Acyl Cyanides". Angewandte Chemie International Edition . 41 (12): 2113– 2116. doi :10.1002/1521-3773(20020617)41:12< 2113::AID-ANIE2113> 3.0.CO; 2-Q . PMID 19746613 .
![{\displaystyle {\color {red}{\mathrm {R} {-}\mathrm {C} (\mathrm {O} )\mathrm {C} }}{\mathrm {H} {=}}{\color {red}{\mathrm {N} }}{\mathrm {OH} }\longrightarrow {\color {red}{\mathrm {R} {-}\mathrm {C} (\mathrm {O} )\mathrm {CN} }}+{\mathrm {H} {\vphantom {A}}_{\smash[{t}]{2}}\mathrm {O} }}](https://wikimedia.org/api/rest_v1/media/math/render/svg/a63f484ba37f8d2a8b66c77a9a9242d7505e8133)
![{\displaystyle {\mathrm {CH} {\vphantom {A}}_{\smash[{t}]{2}}{=}}{\color {red}{\mathrm {C} {=}\mathrm {O} }}+{\mathrm {H} }{\color {red}{\mathrm {CN} }}\longrightarrow {\mathrm {H} {\vphantom {A}}_{\smash[{t}]{3}}\mathrm {C} {}-{}}{\color {red}{\mathrm {C} (\mathrm {O} )\mathrm {CN} }}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/fe3d18d1da39298909f88c97ba548875a982c38e)
![{\displaystyle {\color {red}{\mathrm {R} {-}\mathrm {C} (\mathrm {O} )\mathrm {CN} }}+{2\,\mathrm {NaOH} }\longrightarrow {\color {red}{\mathrm {R} {-}\mathrm {CO} }}{{\vphantom {A}}_{\hphantom {2}}^{\hphantom {}}{\mkern {-1.5mu}}{\vphantom {A}}_{{\vphantom {2}}{\llap {\smash[{t}]{2}}}}^{{\smash[{t}]{\vphantom {2}}}{\llap {}}}\mathrm {Na} }+{\mathrm {Na} }{\color {red}{\mathrm {CN} }}+{\mathrm {H} {\vphantom {A}}_{\smash[{t}]{2}}\mathrm {O} }}](https://wikimedia.org/api/rest_v1/media/math/render/svg/611992c961a288828b80e805b99296470a580a1a)