Dimethyl tetramethylethylenediamine

Abbreviations Aik, alkyl AN, acetonitrile Ar, aryl Bu, butyl cod, 1,5-cyclooctadiene Cp, cy-clopentadienyl Cp , pentamethylcyclopentadienyl Cy, cyclohexyl dppm, diphenylphosphinome-thane dpme, Ph2PC2H4PMe2 Et, ethyl fod, 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octane-dionate HOMO, highest occupied molecular orbital LUMO, lowest unoccupied molecular orbital Me, methyl MO, molecular orbital nbd, norbornadiene Nuc, nucleophile OTf, triflate Ph, phenyl Pr, propyl py, pyridine THE, tetrahydrofuran TMEDA V,V,M,M-tetramethylethylenediamine. 

Stereodivergent aldol addition is also possible when (.S,)-5,5-dimethyl-4-trimethylsiloxy-3-hexanonc (16) is chosen as the enolate precursor. Thus, the lithium enolate generated from 16 by treatment with lithium diisopropylamide and tetramethylethylenediamine leads predomi-... 

Dimethyl- and diethylzinc reacted with dimethylpyrrole- and mesityl-substituted cyclopentadiene ligands to give monocyclopentadienyl(methyl)zinc and -ethyl(zinc) compounds. These products then formed, Scheme 20, crystalline adducts with tetramethylethylenediamine (TMEDA) such as 24, whose solid-state structure is shown in Figure 11. 

AA BAA CMC CPB CTAB DM SO IPC MVPQ PAA PDADMAB PEG PIPAA SDS SMA TEMED acrylamide methylene bisacrylamide critical micelle concentration cetylpyridinium bromide cetyltrimethylammonium bromide dimethylsulfoxide interpolymer complex methylvinylpiridine units quaternized by dimethyl sulfate poly(acrylamide) poly(diallyldimethylammonium bromide) polyethylene glycol) poly(isopropylacrylamide) sodium dodecyl sulfate sodium methacrylate tetramethylethylenediamine... 

SYNTHESIS A solution of 12.1 g N,N,N ,N -tetramethylethylenediamine and 16.6 g of 1,3-diethoxy benzene was made in 200 mL 30-60 °C petroleum ether. This was stirred vigorously under a N2 atmosphere and cooled to 0 °C with an external ice bath. There was added 66 mL of 1.6 M butyllithium in hexane. The stirred reaction mixture became a little cloudy and then gradually formed a white granular precipitate. This was brought to room temperature, stirred for 0.5 h, and returned again to 0 °C. There was added 9.45 g of dimethyl disulfide which converted the loose precipitate to a creamy texture. The reaction was exothermic. After being held 0.5 h at reflux temperature, the reaction mixture was added to 600 mL dilute H2S04. There was the immediate formation of white solids which were insoluble in either phase. The petroleum ether phase was separated, and the aqueous phase extracted... 

A solution of 150 mL of 1.6 M butyl-lithium in hexane under N2 was vigorously stirred and diluted with 150 mL petroleum ether (30-60 °C) and then cooled with an external ice bath to 0 °C. The addition of 26.7 g of veratrole produced a flocculant white precipitate. Next, there was added a solution of 23.2 g of N,N,N ,N -tetramethylethylenediamine in 100 mL anhydrous Et20 and the stirred reaction mixture was allowed to come to room temperature. The subsequent addition of 20.7 g of dimethyl disulfide over the course of several min produced an exothermic response, and this was allowed to stir for an additional 30 min. There was then added 10 mL EtOH followed by 25 0 mL of 5 % NaOH. The organic phase was washed first with 150 mL 5% NaOH, followed by 2x100 mL portions of 5% dilute HC1. The removal of solvent and bulb-to-bulb distillation of the residue provided 2,3-... 

Simple benzamides undergo slow deprotonation with amide bases. Stronger base systems such as. r-butyllithium in tetramethylethylenediamine (TMEDA) are too nucleophilic for sinqrle benzamides but /V,N-dimethyl-2,4,6-triisopropylbenzamide is deprotonated in only 5 min at -78 C, and this anion is alkylated with methyl iodide to give a 77% yield of Ae expected product. ... 

The ring-opening polymerization of 1. l-dimethyl-l-silacyclopent-S-ene, 1 -methyl-1 -phenyl-1 -silacyclopent-3-ene, 1,1 -diphenyl-1 -silacy-clopent-3-ene, and lJ,3-trimethyl-l-silacyclopent-3-ene was catalyzed by alkyllithium reagents in the presence of hexamethyl-phosphoramide or, N -tetramethylethylenediamine and... 

The parent 1,2-thiarsole 32 was prepared according to the reaction sequence shown in Scheme 13. Commercially available allylmercaptan was first lithiated with BuLi/TMEDA and then reacted with dimethyltin dichloride to afford crystalline 2,3-dihydro-2,2-dimethyl-l,2-thiostannole 31 (TMEDA = tetramethylethylenediamine). Heating 31 with AsBt3 in diglyme followed by treatment with l,8-diazabicyclo[5.4.0]undec-7-ene (DBU) yielded the 1,2-thiarsole 32, which was isolated by distillation in 56% yield <2000JA7012>. 

In addition 3-methylmorphol was condensed with /kdimethylamino-ethyl chloride to give 3-methyl-4-(/3-dimethylaminoethyl)-morphol [xxxvn], which was unaffected by sodium ethoxide at 150° C., but was degraded to 3-methyl-4-acetylmorphol [xxvn, R = Ac] and /S-dimethyl-aminoethanol on heating with acetic anhydride, and to morphol [xxi], /3-dimethylaminoethanol, and tetramethylethylenediamine on heating with hydrogen chloride [52],... 

---