Exploring the chemistry of backbone amino(chloro)phosphanyl-substituted imidazole-2-thionesElectronic supplementary information (ESI) available. CCDC 1550750-1550753. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7dt01859b

• Main Authors: Koner, Abhishek, Serin, Spencer C, Schnakenburg, Gregor, Patrick, Brian O, Gates, Derek P, Streubel, Rainer
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c7dt01859b

Backbone (R′ 2 N) 2 P-substituted imidazole-2-thiones 2a-c [(R′ 2 N) 2 P-IMS R,R ; IMS R,R = 1,3-dialkylimidazole-2-thione-4-yl, a : R = i Pr, R′ = Et; b : R = Mes, R′ = Et, c : R = Me, R′ = i Pr] were treated with PCl 3 to synthesize R′ 2 N(Cl)P-substituted imidazole-2-thiones 3a-c [R′ 2 N(Cl)P-IMS R,R ]. The P -chloro compounds 3a,b were used to explore the chemistry further, i.e. nucleophilic substitution at phosphorus using Ph 2 CHLi or fluorenyl lithium afforded compounds 4a-c [R′ 2 N(R′′)P-IMS R,R ; a : R = i Pr, R′ = Et, R′′ = PH 2 CH; b : R = Mes, R′ = Et, R′′ = Flu c : R = i Pr, R′ = Et, R′′ = Flu]. Compound 4c was used to access the P -borane adduct 5 [R′ 2 N(R′′)(BH 3 )P-IMS R,R ; R = i Pr, R′ = Et, R′′ = Flu] and phosphinoyl-substituted imidazolium hydrogensulfate 6 [[R′ 2 N(R′′)(O)P-IMH R,R ]HSO 4 ; IMH R,R = 1,3-dialkylimidazolium-4-yl, R = i Pr, R′ = Et, R′′ = Flu]. Compounds 4a,b were transformed into the P -Cl compounds 7a,b [R′′(Cl)P-IMS R,R ; a : R = i Pr, R′′ = Ph 2 CH; b : R = Mes, R′′ = Flu] which represent potential starting materials for backbone phosphaalkenyl substituted imidazole-2-thiones. Compound 7a yielded the NHC-stabilized phosphenium salt 8 [[R′′(IMe 4 )P-IMS R,R ]Cl; R = i Pr, R′ = Et, R′′ = Ph 2 CH, IMe 4 = 1,3,4,5-tetramethylimidazole-2-ylidene] in reaction with 1,3,4,5-tetramethylimidazole-2-ylidene (IMe 4 ). Attempts to deprotonate 7a,b using n BuLi revealed that nucleophilic substitution of P -Cl to give the P - n Bu product occurred preferentially, and dehydrochlorination to the phosphaalkene was not observed. Backbone amino(chloro)phosphanyl-substituted imidazole-2-thiones were synthesized and their potential as starting material for backbone phosphaalkenyl substituted imidazole-2-thiones studied.