(Chloromethylene)triphenylphosphorane

(Chloromethylene)triphenylphosphorane is the organophosphorus compound with he formula Ph₃P=CHCl (Ph = phenyl). It is a white solid but is usually generated and used in situ as a reagent in organic synthesis. It is structurally and chemically related to methylenetriphenylphosphorane.

(Chloromethylene)triphenyl­phosphorane

Names
Preferred IUPAC name (Chloromethylidene)tri(phenyl)-λ5-phosphane
Identifiers
CAS Number	29949-92-6
3D model (JSmol)	Interactive image
ChemSpider	366640
PubChem CID	414080
CompTox Dashboard (EPA)	DTXSID601336672
InChI InChI=1S/C19H16ClP/c20-16-21(17-10-4-1-5-11-17,18-12-6-2-7-13-18)19-14-8-3-9-15-19/h1-16H Key: KIZBYQRDCHVQID-UHFFFAOYSA-N
SMILES C1=CC=C(C=C1)P(=CCl)(C2=CC=CC=C2)C3=CC=CC=C3
Properties
Chemical formula	C19H16ClP
Molar mass	310.76 g·mol−1
Appearance	white solid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The reagent is prepared from the chloromethylphosphonium salt [Ph₃PCH₂Cl]Cl by treatment with strong base. The phosphonium compound is generated by treatment of triphenylphosphine with chloroiodomethane.^[1]

(Chloromethylene)triphenylphosphorane converts aldehydes to vinyl chlorides:

RCHO + Ph₃P=CHCl → RCH=CHCl + Ph₃PO

These vinyl chlorides undergo dehydrochlorination to give alkynes:^[2]

RCH=CHCl + NaN(SiMe₃)₂ → RC≡CH + NaCl + HN(SiMe₃)₂