13365-08-7Relevant academic research and scientific papers
Selective metalation of 4,6-dibromoresorcinol dimethyl ether with LiTMP
Kraus, George A.,Jeon, Insik,Mengwasser, John,West, Aaron C.,Windus, Theresa L.
experimental part, p. 1955 - 1958 (2010/10/03)
4,6-Dibromoresorcinol dimethyl ether was selectively metalated at C-5 with lithium tetramethylpiperidide (LiTMP). A rationale for the selective metalation is proposed. Georg Thieme Verlag Stuttgart.
Reductive cleavage of the carbon-phosphorus bond with alkali metals. II. Cleavage of mixed functionalized triarylphosphines; Birch reduction of arylphosphines
Doorn, Johannes A. van,Frijns, John H. G.,Meijboom, Nico
, p. 441 - 449 (2007/10/02)
The reductive cleavage of mixed ortho- and para-functionalized triarylphosphines with Na/NH3 and Li/THF depends strongly on the nature and positions of the substituents.Reduction occurs readily with phosphines PhAr2P (4, 6 and 9) and Ph2ArP 19 when the corresponding phosphine Ar3P is not reduced.Cleavage of para-substituted compounds 7 and 9 leads to mixtures of secondary phosphines.By contrast, cleavage of mixed ortho-substituted triphenylphosphines is very selective.The functionalized phenyl group is split off in high yield when it carries CH3, (CH3)2N and CH3O substituents (2, 3, 5, 6, 8, 10, 11, 13, 14, 17, 19, 24, 25).Reaction of 4 is not selective due to loss of methoxy groups (1, 15, 16).The reactions of bis- and tris(diphenylphosphino)benzenes with Li/THF leads predominantly to cleavage of the diphenylphosphino group from the respective substrates.In a number of cases, the product of a Birch reduction with an isolated diene system is formed in NH3 (1, 9, 12, 21, 23) via a phosphino-stabilized cyclohexadienyl anion.This reduction does not occur in the aprotic solvent THF.Base-catalyzed isomerization leads to a conjugated double-bond system with a vinylphosphine moiety.We also report interesting large 4J(PP) couplings in 1,3-diphosphinobenzenes and complicated 13C resonances of para-substituted phosphines.
