103192-30-9Relevant academic research and scientific papers
A Convenient Synthesis of 9,9-Dialkyl-9,10-dihydroanthracenes and 10,10-Dialkylanthrones: Silicon-Mediated Regioselective Dialkylation of 9,10-Dihydroanthracene
Dhar, Raj K.,Clawson, D. K.,Fronczek, Frank R.,Rabideau, Peter W.
, p. 2917 - 2921 (2007/10/02)
Described is a short and convenient approach to the synthesis of 9,9-dialkyl-9,10-dihydroanthracenes, 9,9,10-trialkyl-9,10-dihydroanthracenes, and 10,10-dialkylanthrones, some of which are otherwise unknown or inaccessible by conventional methods.Deprotonation of 9-(trimethylsilyl)-9,10-dihydroanthracene (2; 9-(trimethylsilyl)-9,10-DHA) followed by reaction with alkyl halides (RX) produces 9-alkyl-9-(trimethylsilyl)-9,10-DHAs 3-7 in 80-90percent yields.Treatment of 3-7 with n-BuLi produces the 10-lithio derivatives that rearrange to 9-alkyl-9-lithio-10-(trimethylsilyl) intermediates; subsequent alkylation with RX generates 9,9-dialkyl-10-(trimethylsilyl)-9,10-DHAs 8-19.Formation of single stereoisomers 13-19 was suggested by NMR and confirmed in two cases, 15 and 16, by X-ray structure determination.The trimethylsilyl group is removed by tetrabutylammonium fluoride (TBAF) to provide 9,9-dialkyl-9,10-DHAs 20-29 with impressive yields.Oxidation of either the 9,9-dialkyl-9,10-DHAs or 9,9-dialkyl-10-(trimethylsilyl)-9,10-DHAs with Cr(VI) oxidant furnished 10,10-dialkylanthrones 36-41 in 80-90percent yields.
Silicon Mediated Alkylations in the 9,10-Dihydroanthracene System: A Convenient Synthesis of 9,9-Dialkyl-9,10- Dihydroanthracenes
Rabideau, Peter W.,Dhar,Clawson,Zhan, Zhengyun
, p. 3969 - 3972 (2007/10/02)
A trimethylsilyl (TMS) substituent is used to control the regiochemistry of alkylation in 9,10-dihydroanthracene (9,10-DHA) furnishing 9,9-dialkyl-10-TMS-9,10-DHAs. The TMS group is subsequently removed resulting in the first convenient synthesis of a var
The Nature of 9-Substituted 9,10-Dihydroanthracene Monoanions Formed by the Monoprotonation of Dianions and the Deprotonation of Dihydroaromatics
Rabideau, Peter W.,Maxwell, Andrew J.,Sygula, Andrzej
, p. 3181 - 3184 (2007/10/02)
The production of monoanions of the type 9-R-10-metallo-9,10-dihydroanthracene and 9-R-9-metallo-9,10-dihydroanthracene is accomplished by two methods.Method A involves the addition of sodium metal to 9-R-anthracene in anhydrous ammonia/THF.Protonation of the dianion intermediate by ammonia produces a monoanion which persists.In method B, 9-R-9,10-dihydroanthracenes are deprotonated by n-butyllithium in THF.By method A, methylation produces a mixture of 9-R-10-methyl-9,10-dihydroanthracene and 9-R-9-methyl-9,10-dihydroanthracene with the latter predominanting in all cases (R= Me, Et, n-Bu, i-Pr, Bz, Ph).By method B, only the 9,10-isomers are produced (except for R = Ph).Mechanistic implications are discussed, and MNDO calculations are presented for both dianions and monoanions.
