479-71-0Relevant articles and documents
Silver-Catalyzed Regioselective Phosphorylation of para-Quinone Methides with P(III)-Nucleophiles
Liu, Yu,Tang, Ke-Wen,Wong, Wai-Yeung,Xie, Jun,Xiong, Biquan,Xu, Shipan,Xu, Weifeng
, p. 14983 - 15003 (2021/11/12)
A simple and efficient method for the silver-catalyzed regioselective phosphorylation of para-quinone methides (p-QMs) with P(III)-nucleophiles (P(OR)3, ArP(OR)2, Ar2P-OR) has been established via Michaelis-Arbuzov-type reaction. A broad range of P(III)-nucleophiles and para-quinone methides are well tolerated under the mild conditions, giving the expected diarylmethyl-substituted organophosphorus compounds with good to excellent yields. Moreover, a series of corresponding enantiomers can be obtained by employing dialkyl arylphosphonite (ArP(OR)2) as substrates. The control experiments and 31P NMR tracking experiments were also performed to gain insights for the plausible reaction mechanism. This protocol may have significant implications for the formation of C(sp3)-P bonds in Michaelis-Arbuzov-type reactions.
The synthesis of novel p-quinone methides: O-dealkylation of 5-(p-alkyloxyaryl)-10,11-dihydrodibenzo[a,d]cyclohepten-5-ols and related compounds
Taljaard, Benjamin,Taljaard, Jana H.,Imrie, Christopher,Caira, Mino R.
, p. 2607 - 2619 (2007/10/03)
The synthesis of a series of novel tricyclic p-quinone methides (p-QMs) from 5-(p-alkyloxyaryl)-10,11-dihydrodibenzo[a,d]cyclohepten-5-ol and related substrates in moderate-to-good yields is reported. The reaction is proposed to proceed under mild acidic conditions by O-dealkylation of the p-alkoxy group on the p-position of the pendant 5-aryl ring on the B-ring of the tricyclic system.The effect of different alkyl groups on the oxygen atom, as well as substituent groups on the phenyl ring flanking the O-alkyl group has also been investigated The mechanism of the reaction is discussed in terms of the relatively high intermediate cation stabilities, the possible intermediacy of a hemiketal, as well as conformational effects. Various modifications to the central seven-membered B-ring to introduce more rigidity to the tricyclic system have been made and the scope of the reaction further elaborated. Furthermore, the single crystal structure of dienone 14 has been determined and the p-quinone methide shown to be non-planar, which would account for the relative conformational rigidity of these systems and their ability to accommodate the planar cyclohexa-2,5-dienone moiety and thus explain the stability of these systems relative to their 5- and six-membered B-ring counterparts. These compounds may be useful for the synthesis of novel dyes or compounds which may exhibit photochromic and thermochromic properties. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).
Oxidation of nitrobenzylic carbanions with dimethyldioxirane. New synthesis of quinomethanes and nitrobenzylic carbinols. First examples of methylation of carbanions with dimethyldioxirane
Makosza,Adam,Zhao,Surowiec
, p. 5022 - 5026 (2007/10/03)
The reaction of nitrobenzylic carbanions with dimethyldioxirane (DMD) results in oxidation at the carbanion center or at the nitronate center to give nitrobenzylic carbinols or quinomethanes, respectively. Minor amounts of the methylation products are also formed. Both of these processes were observed for carbanions of (p-nitroaryl)diarylmethanes. The outcome of the oxidation process is very sensitive to the reaction conditions.
