77613-54-8

Basic information

• Product Name: 4-(4-Chloro-phenyl)-2,2,2-triphenyl-2λ⁵-[1,2]oxaphosphetane
• Synonyms: 4-(4-Chloro-phenyl)-2,2,2-triphenyl-2λ⁵-[1,2]oxaphosphetane
• CAS NO: 77613-54-8
• Molecular Weight: 416.887
• Mol File: 77613-54-8.mol
• Article Data: 1

Chemical Properties

• CAS DataBase Reference: 4-(4-Chloro-phenyl)-2,2,2-triphenyl-2λ⁵-[1,2]oxaphosphetane(CAS DataBase Reference)
• NIST Chemistry Reference: 4-(4-Chloro-phenyl)-2,2,2-triphenyl-2λ⁵-[1,2]oxaphosphetane(77613-54-8)
• EPA Substance Registry System: 4-(4-Chloro-phenyl)-2,2,2-triphenyl-2λ⁵-[1,2]oxaphosphetane(77613-54-8)

Safety Data

• Hazardous Substances Data: 77613-54-8(Hazardous Substances Data)

Upstream product

• 104-88-1 4-chlorobenzaldehyde 
• 19493-09-5 Methylenetriphenylphosphorane 
• 1779-49-3 Methyltriphenylphosphonium bromide 

Relevant articles and documents

Low-temperature characterization of the intermediates in the Wittig reaction

Nonstabilized salt-free ylides react with aldehydes and nonhindered or strained ketones at -78°C to give oxaphosphetanes. The Wittig intermediates can be observed by 31P and 1H NMR techniques. In the presence of LiBr, betaine-lithium bromide adducts often precipitate from solution. The oxaphosphetane from PhCHO + CH2=PPh3 reacts rapidly with LiBr to give a betaine·LiBr adduct, and the corresponding salt Ph3P+CH2CHOHPh Br- reacts with KH at -40°C to form the oxaphosphetane. No salt-free betaine has been detected. Lithium bromide is shown to decrease cis selectivity (CH3CH=PPh3 + PhCH2CH2CHO) in the condensation step and not by oxaphosphetane equilibration. Oxaphosphetane reversal to ylide + aldehyde is confirmed for aryl aldehydes but not for aliphatic aldehydes or ketones according to three types of crossover experiments. Rationales for cis selectivity of aldehyde-ylide reactions are discussed. A "crisscrossed" cycloaddition rationale is proposed, aldehyde and ylide planes tilted toward an orthogonal arrangement to minimize steric interactions, to explain cis-alkene formation. Other transition-state geometries having carbonyl and ylide planes roughly parallel are considered more likely for trans-olefin formation or for Wittig reactions of ketones.