Hydrogen Cyanide

Enantioselective Olefin Hydrocyanation without Cyanide

“…Asymmetric olefin hydrocyanation is typically achieved through the formal addition of hydrogen cyanide, either generated in situ or employed directly in gaseous form, across an olefin facilitated by a chiral phosphine-ligated metal catalyst (Figure A). , Aside from the potential safety concerns of working with hydrogen cyanide, many of these asymmetric methods are limited to vinyl arenes and employ noncommercially available ligands. , Recently, Zhang and Lv have described a formal asymmetric olefin hydrocyanation reaction by means of a tandem rhodium-catalyzed hydroformylation/condensation/aza-Cope elimination sequence . Alternative methods to access enantioenriched nitriles, including C–H cyanation, α-arylation of prefunctionalized nitriles, and enantioselective protonation of silyl ketene imines, have also been developed employing various precursors …”

Ex situ gas generation for lab scale organic synthesis

“…59 Direct use of this low-boiling compound (b.p. 26 -27 °C) 60 is usually avoided because of its acute toxicity. [60][61][62] Nevertheless, hydrogen cyanide releasing molecules might mitigate some of the safety concerns associated with handling hydrogen cyanide.…”

“…26 -27 °C) 60 is usually avoided because of its acute toxicity. [60][61][62] Nevertheless, hydrogen cyanide releasing molecules might mitigate some of the safety concerns associated with handling hydrogen cyanide. Most cyanation procedures still rely on a "masked" cyanide reagent, such as cyanide salts delivering -CN ions rather than HCN.…”

Development of an Operationally Simple, Scalable, and HCN-Free Transfer Hydrocyanation Protocol Using an Air-Stable Nickel Precatalyst

“…In this transformation, hydrogen cyanide (HCN) is formally added across an alkene or an alkyne yielding the corresponding aliphatic or alkenyl nitriles, respectively. − One of the most prominent industrial applications of the hydrocyanation reaction is the DuPont process (Scheme A) . The catalytic system, relying on a nickel–phosphite catalyst, has enabled the production of adiponitrile, a common precursor for Nylon 66, by the incorporation of HCN into butadiene on a 1-million-ton scale annually. − Despite this notable commercial application of this homogeneously catalyzed hydrocyanation reaction, the use of highly volatile HCN in laboratory-scale settings has been limited due to its extreme toxicity, as well as its explosive and corrosive nature …”