150-77-6

Basic information

• Product Name: N,N,N',N'-TETRAETHYLETHYLENEDIAMINE
• Synonyms: TEEN;N,N,N',N'-TETRAETHYLETHYLENEDIAMINE;2-Ethanediamine,N,N,N’,N’-tetraethyl-1;Ethylenediamine, N,N,N',N'-tetraethyl-;N,N,N',N'-Tetraethylenediamine;n,n,n’,n’-tetraethyl-2-ethanediamine;N,N,N’,N’-tetraethyl-ethane-1,2-diamine;N,N,N’,N’-Tetra-ethylethylendiamine
• CAS NO: 150-77-6
• Molecular Formula: C₁₀H₂₄N₂
• Molecular Weight: 172.31
• EINECS: 205-770-3
• Product Categories: Nitrogen Compounds;Organic Building Blocks;Polyamines;Building Blocks;Chemical Synthesis;Nitrogen Compounds;Organic Building Blocks
• Mol File: 150-77-6.mol
• Article Data: 9

Chemical Properties

• Melting Point: 192 °C
• Boiling Point: 189-192 °C(lit.)
• Flash Point: 138 °F
• Appearance: Clear light yellow/Liquid
• Density: 0.808 g/mL at 25 °C(lit.)
• Refractive Index: n20/D 1.4343(lit.)
• PKA: 9.03±0.50(Predicted)
• Sensitive: Moisture Sensitive
• BRN: 1738741
• CAS DataBase Reference: N,N,N',N'-TETRAETHYLETHYLENEDIAMINE(CAS DataBase Reference)
• NIST Chemistry Reference: N,N,N',N'-TETRAETHYLETHYLENEDIAMINE(150-77-6)
• EPA Substance Registry System: N,N,N',N'-TETRAETHYLETHYLENEDIAMINE(150-77-6)

Safety Data

• Hazard Codes: C
• Statements: 34
• Safety Statements: 26-27-36/37/39-45
• RIDADR: UN 2734 8/PG 2
• WGK Germany: 3
• HazardClass: 3
• PackingGroup: III
• Hazardous Substances Data: 150-77-6(Hazardous Substances Data)

Usage

Chemical Properties

clear light yellow liquid

Uses

N,N, N′,N′-Tetraethylethylenediamine (TEEDA) has been used in the synthesis of amine ligands using simple or double intramolecular dealkylation reaction. TEEDA exhibits selective β-lithiation during deprotonation with lithiumalkyls.

Synthetic route

ethanol (64-17-5) + ethylenediamine (107-15-3) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With hydrogen at 180℃; under 7500.75 Torr;	76.3%
With hydrogen at 180℃; under 7500.75 Torr;	76.3%

chloroethane (75-00-3) + ethylenediamine (107-15-3) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
	60%

N,N,N',N'-tetraethyloxamide (14288-05-2) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With lithium aluminium tetrahydride; diethyl ether

ethyl iodide (75-03-6) + ethylenediamine (107-15-3) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
als Bis-hydrojodid;

ethene (74-85-1) + ethylenediamine (107-15-3) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With n-heptane; sodium at 200℃; under 588406 - 735508 Torr;

ethene (74-85-1) + ethylenediamine (107-15-3) → N,N'-diethylethylenediamine (111-74-0) + N,N,N'-triethylethanediamine (105-04-4) + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + N,N-diethylethylenediamine (100-36-7)

Conditions	Yield
analog reagieren wie das Butylamin;

ethylene dibromide (106-93-4) + diethylamine (109-89-7) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With copper; benzene Unter Druck;

ethyleneglycol dibenzenesulfonate (116-50-7) + diethylamine (109-89-7) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With 1,4-dioxane

diethylamine (109-89-7) + 2-(diethylamino)ethyl chloride (100-35-6) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With benzene at 100℃;

N,N-diethylnmethylamine (616-39-7) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
(γ-irradiation);

tetra-N-ethyl-trans-ethene-1,2-diamine (20155-68-4, 91889-60-0) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With formic acid

hydroxyprocaine (487-53-6) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
at 160 - 180℃;

2-(diethylamino)ethyl chloride (100-35-6) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With magnesium

ethylene glycol (107-21-1) + diethylamine (109-89-7) → N,N,N',N'-Tetraethylethylenediamine (150-77-6) + 2-(Diethylamino)ethanol (100-37-8)

Conditions	Yield
With tris(triphenylphosphine)ruthenium(II) chloride at 120℃; for 2h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;
With ruthenium trichloride at 120℃; for 2.5h; Yield given. Yields of byproduct given. Title compound not separated from byproducts;

1,2-dichloro-ethane (107-06-2) + diethylamine (109-89-7) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With sodium carbonate In N,N-dimethyl-formamide at 52℃; Kinetics; Further Variations:; Temperatures; Substitution;

diethylamine (109-89-7) + 2-chloro-triethylamine hydrochloride → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

diethylamine (109-89-7) + benzenesulfonic acid-<β-chloro-ethyl ester> → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

ethylene dibromide (106-93-4) + diethylamine (109-89-7) → N,N,N',N'-Tetraethylethylenediamine (150-77-6) + octaethyltriethylenetetraammonium bromide

Conditions	Yield
als Bis-hydrobromid;

triethylamine (121-44-8) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
Multi-step reaction with 2 steps 1: benzene 2: lithium alanate; diethyl ether View Scheme

ethanol (64-17-5) + ethylenediamine (107-15-3) → N-ethylethane-1,2-diamine (110-72-5) + N,N'-diethylethylenediamine (111-74-0) + N,N,N'-triethylethanediamine (105-04-4) + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + N,N-diethylethylenediamine (100-36-7)

Conditions	Yield
With hydrogen at 200℃; under 7500.75 Torr; for 8h; Product distribution / selectivity;

bromobenzene (108-86-1) + (teeda)*H2SiCl2 → biphenyl (92-52-4) + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + diphenylsilane (775-12-2)

Conditions	Yield
Stage #1: bromobenzene With magnesium In tetrahydrofuran; ethylene dibromide Stage #2: (teeda)*H2SiCl2 In tetrahydrofuran; dichloromethane; ethylene dibromide

bromobenzene (108-86-1) + diethyl ether (60-29-7) + (teeda)*H2SiCl2 → biphenyl (92-52-4) + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + diphenylsilane (775-12-2) + 1,1,3,3-tetraphenyldisiloxane (15545-80-9) + ethoxy(diphenyl)silane (18407-46-0)

Conditions	Yield
Stage #1: bromobenzene With magnesium In diethyl ether; ethylene dibromide Stage #2: diethyl ether; (teeda)*H2SiCl2 In dichloromethane; ethylene dibromide	A 9 %Chromat. B 26 %Chromat. C 35 %Chromat. D 14 %Chromat. E 13 %Chromat.

D-glucose (50-99-7) + diethylamine (109-89-7) → N,N,N',N'-Tetraethylethylenediamine (150-77-6)

Conditions	Yield
With 5 wt% ruthenium/carbon; hydrogen In water at 124.84℃; under 56255.6 Torr; for 1h;	33 %Spectr.

zinc hydride + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + carbon dioxide (124-38-9) → [(N,N,N’,N’-tetraethylethane-1,2-diamine)Zn(OCHO)2]

Conditions	Yield
In dichloromethane at 20℃; under 750.075 Torr; Schlenk technique;	98%

zinc hydride + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + [(N,N,N’,N’-tetraethylethane-1,2-diamine)ZnH]2[B(3,5-(CF3)2-C6H3)4]2 → [(N,N,N’,N’-tetraethylethane-1,2-diamine)2Zn2H3][B(3,5-(CF3)2-C6H3)4]

Conditions	Yield
In tetrahydrofuran at 20℃; for 0.25h; Inert atmosphere;	98%

triethylammonium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate + N,N,N',N'-Tetraethylethylenediamine (150-77-6) → C10H24N2*H(1+)*C32H12BF24(1-)

Conditions	Yield
In diethyl ether at 20℃; Inert atmosphere;	97%

zinc hydride + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + [(N,N,N’,N’-tetramethylethane-1,2-diamine)ZnH(thf)][B(3,5-(CF3)2-C6H3)4] → [{(N,N,N’,N’-tetraethylethane-1,2-diamine)Zn(μ-H2)}{((N,N,N’,N’-tetramethylethane-1,2-diamine)ZnH)2}][B(3,5-(CF3)2-C6H3)]2

Conditions	Yield
In tetrahydrofuran at 20℃; for 0.25h; Inert atmosphere;	95%

C52H43Cl5N2O2S2 + N,N,N',N'-Tetraethylethylenediamine (150-77-6) → 2-[[(2-Diethylamino-ethylcarbamoyl)-methyl]-(2-tritylsulfanyl-ethyl)-amino]-N-(2-tritylsulfanyl-ethyl)-acetamide (371161-09-0)

Conditions	Yield
With N-isopropylethylamine In dichloromethane at 20℃; for 1h;	94%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + palladium dichloride → N,N,N',N'-tetraethylethylenediamine palladium(II) chloride (166896-59-9)

Conditions	Yield
In acetonitrile under N2 atm. to hot soln. PdCl2 in MeCN ligand was added; mixt. was cooled to room temp.. kept at 5°C overnight, ppt. was filtered off, washed with Et2O, dried under vac.;	94%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + 2-methyl-1,3-cyclopentadiene (3727-31-9) + zinc(II) chloride (7646-85-7) → (zinc)(η**(1)-methylcyclopentadienyl)2(N,N,N',N'-tetraethylethylenediamine) (1342797-20-9)

Conditions	Yield
With NaH In tetrahydrofuran C5H5CH3 added dropwise to NaH in THF at 0°C; left for 2 h at ambient temp.; centrifuged, added slowly to THF soln. of ZnCl2; stirred at ambient temp. overnight; crystals redissolved in THF, tetraethylethylenediamine added; left at -80°C;	94%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + boric acid (11113-50-1) → C10H24N2*2H(1+)*2B5H4O10(1-)

Conditions	Yield
In water at 20℃; for 1h;	91%

[CpNi(SMe2)2]BF4 + N,N,N',N'-Tetraethylethylenediamine (150-77-6) → (C5H5)Ni((C2H5)2NCH2CH2N(C2H5)2)(1+)*BF4(1-)=((C5H5)Ni((C2H5)2NCH2CH2N(C2H5)2))BF4

Conditions	Yield
In nitromethane byproducts: S(CH3)2; a soln. of Ni-complex in MeNO2 was treated with 1 equiv of diamine under inert atmosphere, mixt. was stirred for 10 min at room temp.; reaction mixt. was filtered into Et2O, ppt. filtered off, washed with ether, dried under high vac.; elem. anal.;	89%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + 2-Naphthalenesulfonyl chloride (93-11-8) → N,N-diethylnaphthalene-2-sulfonamide (6307-08-0)

Conditions	Yield
With calcium hydride In acetonitrile at 90℃; for 1h; Inert atmosphere; Schlenk technique; regiospecific reaction;	89%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + p-toluenesulfonyl chloride (98-59-9) → N,N-diethyl-4-methylbenzenesulfonamide (649-15-0)

Conditions	Yield
In acetonitrile at 90℃; for 1h; Inert atmosphere;	87%
With calcium hydride In acetonitrile at 90℃; for 1h; Inert atmosphere; Schlenk technique; regiospecific reaction;	87%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + 4-bromobenzenesulfonyl chloride (98-58-8) → 4-bromo-N,N-diethylbenzenesulfonamide (90944-62-0)

Conditions	Yield
With calcium hydride In acetonitrile at 90℃; for 1h; Inert atmosphere; Schlenk technique; regiospecific reaction;	86%

uranyl nirate hexahydrate + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + diethyl malonic acid (510-20-3) + water (7732-18-5) → N,N,N',N'-tetraethylethylenediammonium bis(diethylmalonato) aqua dioxouranate(VI) dihydrate

Conditions	Yield
In water a soln. of U compd. added to a soln. of a ligand and a diamine (1:2:2 molar ratio), stored for a 1 wk; ppt. filtered, dried (air); elem. anal., TGA;	85%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + zinc dibromide → [ZnBr2(TEEDA)] (1256760-66-3)

Conditions	Yield
In dichloromethane; acetone	85%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) → N,N'-Diamino-N,N,N',N'-tetraethyl-1,2-ethanediylbis(ammonium nitrate) (138385-72-5)

Conditions	Yield
With barium(II) nitrate; barium(II) oxide; hydroxylamine-O-sulfonic acid In water Ambient temperature;	82%

tris(ethene)nickel(0) (50696-82-7) + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + 1,1-Difluoro-1H-cyclopropabenzol (18238-55-6) → Ni(N(CH2CH3)2CH2CH2N(CH2CH3)2)(CH2CH2C(CF2)(CH)4C)

Conditions	Yield
In diethyl ether byproducts: C2H4; diamine added at -78°C to a soln. of Ni-compd. (fresh prepd. from CDT-Ni), filtered with cooling, benzene compd. added at -78°C, warmed to -30.degreee.C; after 3 h cooled to -78°C, isolated, washed with cold Et2O, dried in high vac., recrystn. from Et2O/THF, elem. anal.;	82%

nickel(II) bromide dimethoxyethane + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + (trifluoromethyl)trimethylsilane (81290-20-2) → [(N,N,N,N-tetraethylethane-1,2-diamine)Ni(CF3)2] (1437789-01-9)

Conditions	Yield
Stage #1: (trifluoromethyl)trimethylsilane With silver fluoride In acetonitrile at 20℃; for 2h; Inert atmosphere; Stage #2: nickel(II) bromide dimethoxyethane In acetonitrile for 48h; Inert atmosphere; Stage #3: N,N,N',N'-Tetraethylethylenediamine at 20℃; for 4h;	82%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + 2-bromoethanol (540-51-2) → C12H29N2O(1+)*Br(1-)

Conditions	Yield
In acetonitrile at 20℃; for 10h;	80.3%

thiophene-2-sulfonyl chloride (16629-19-9) + N,N,N',N'-Tetraethylethylenediamine (150-77-6) → N,N-Diethyl-2-thiophenesulfonamide (41895-11-8)

Conditions	Yield
With calcium hydride In acetonitrile at 90℃; for 1h; Inert atmosphere; Schlenk technique; regiospecific reaction;	79%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + zinc(II) chloride (7646-85-7) → C10H24Cl2N2Zn

Conditions	Yield
In ethanol at 25℃; for 1h; Inert atmosphere;	78%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + 1,1,1,3',3',3'-hexafluoro-propanol (920-66-1) + copper(II) methoxide (1184-54-9, 18213-24-6) → bis(1,1,1,3,3,3-hexafluoro-2-propoxo)(N,N,N',N'-tetraethylethylenediamine)copper(II) (143924-03-2)

Conditions	Yield
In diethyl ether byproducts: CH3OH; (under vac. or Ar); addn. of the amine and the fluoropropanol to a suspn. of the Cu(OMe)2 in Et2O at room temp., stirring for 30 min; filtration, concg., cooling to -20°C;	77%

uranyl nirate hexahydrate + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + water (7732-18-5) + 2,2-dimethylmalonic acid (595-46-0) → tetraethylethylenediammonium triis(dimethylmalonato) bis[dioxouranate(VI)] monohydrate

Conditions	Yield
In water U:acid:amine=2:4:4 molar ratio, mixed the solns., allowed to stand for 1wk; ppt. filtered, dried (air); elem. anal., TGA;	75%

uranyl nirate hexahydrate + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + diethyl malonic acid (510-20-3) + water (7732-18-5) → N,N,N',N'-tetraethylethylenediammonium pentakis(diethylmalonato) tris[dioxouranate(VI)] dihydrate

Conditions	Yield
In water a soln. of U compd. added to a soln. of a ligand and a diamine (1:2:2 molar ratio), stored for a 1 wk at 30°C; ppt. filtered, dried (air); elem. anal., TGA;	75%

dichloro(1,5-cyclooctadiene)ruthenium(II) + N,N,N',N'-Tetraethylethylenediamine (150-77-6) → trans-[RuCl2(1,5-cyclooctadiene)(N,N'-diethylethylenediamine)] (495413-66-6)

Conditions	Yield
In toluene (N2); addn. of amine deriv. to stirred suspn. of ruthenium compd. in toluene, heating at 80°C for 24 h; cooling to room temp., evapn., recrystn. (diethyl ether/CH2Cl2 (3:1)) at-20°C;	75%

[BeBr2(OEt2)2] (93785-54-7) + N,N,N',N'-Tetraethylethylenediamine (150-77-6) → BeBr2(N,N,N’,N’-tetraethylethylenediamine)

Conditions	Yield
In toluene at 20℃; for 15h; Schlenk technique; Glovebox; Inert atmosphere;	75%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + cobalt acetylacetonate → bis(2,4-pentanedionate)(N,N,N',N'-tetraethyl-1,2-diaminoethane)cobalt(II) (116128-94-0)

Conditions	Yield
In toluene N2 atmosphere; azeotropic removal of H2O from Co(acac)2 in toluene, cooling, addn. of org. compd. (10 % excess),; cooling and filtn. or crystn. on removal of solvent, recrystn. (hexane/toluene, -20°C);	74%

zinc hydride + N,N,N',N'-Tetraethylethylenediamine (150-77-6) + C10H24N2*H(1+)*C32H12BF24(1-) → [(N,N,N’,N’-tetraethylethane-1,2-diamine)2Zn2H3][B(3,5-(CF3)2-C6H3)4]

Conditions	Yield
In tetrahydrofuran at 20℃; for 0.25h; Inert atmosphere;	74%

ruthenium(II)(2,5-norbornadiene)Cl2 + N,N,N',N'-Tetraethylethylenediamine (150-77-6) → trans-[RuCl2(2,5-norbornadiene)(N,N,N'-triethylethylenediamine)] (495413-65-5)

Conditions	Yield
In toluene (N2); addn. of amine deriv. to stirred suspn. of ruthenium compd. in toluene, heating at 80°C for 24 h; cooling to room temp., evapn., recrystn. (diethyl ether/CH2Cl2 (6:1)) at-20°C;	73%

N,N,N',N'-Tetraethylethylenediamine (150-77-6) + 1,1,1,5,5,5-hexafluoro-4-hydroxy-pent-3-en-2-one; compound with N,N,N'-triethyl-ethane-1,2-diamine → (E)-4-(2-Diethylamino-ethylamino)-1,1,1,5,5,5-hexafluoro-pent-3-en-2-one

Conditions	Yield
Stage #1: 1,1,1,5,5,5-hexafluoro-4-hydroxy-pent-3-en-2-one; compound with N,N,N'-triethyl-ethane-1,2-diamine With phenyldimethylsilyl chloride In diethyl ether Heating; Stage #2: N,N,N',N'-Tetraethylethylenediamine at -78 - 20℃;	72%

Upstream product

• 75-03-6 ethyl iodide 
• 107-15-3 ethylenediamine 
• 487-53-6 hydroxyprocaine 
• 75-00-3 chloroethane 
• 107-06-2 1,2-dichloro-ethane 
• 109-89-7 diethylamine 
• 121-44-8 triethylamine 
• 50-99-7 D-glucose 
• 64-17-5 ethanol 
• 108-86-1 bromobenzene 
• 60-29-7 diethyl ether 
• 106-93-4 ethylene dibromide 
• 107-21-1 ethylene glycol 
• 100-35-6 2-(diethylamino)ethyl chloride 

Downstream Products

• 311-91-1 1,1,2,2-tetrafluoro-tetrakis-N-pentafluoroethyl-ethanediyldiamine 
• 171883-35-5 [Pd(phenoxo)2(N,N,N',N'-tetraethylethylenediamine)] 
• 24426-21-9 N,N,N',N'',N''-pentaethyldiethylenetriamine 
• 24426-32-2 N,N,N',N,N',N'-hexaethyltriethylenetetramine 
• 109202-52-0 N-n-butyl-N,N',N'-triethylethylenediamine 
• 93783-07-4 perethyltetraethylenepentamine 
• 121-44-8 triethylamine 
• 50-00-0 formaldehyd 
• 111-74-0 N,N'-diethylethylenediamine 
• 75-07-0 acetaldehyde 
• 109-89-7 diethylamine 
• 105-04-4 N,N,N'-triethylethanediamine 
• 75-04-7 ethylamine 
• 100-36-7 N,N-diethylethylenediamine 

Relevant articles and documents

Kinetic studies of the N-Alkylation of secondary amines with 1, 2-dichloroethane

The reaction of 1,2-dichloroethane with 2-(ethylamino)ethanol or diethylamine have been investigated in several solvents from 51 to 80°C. A reaction mechanism has been proposed where 1, 2-dichloroethane reacts with the secondary amines in both bimolecular substitution (SN 2) and elimination (E2) reactions; the substitution product is rapidly converted in an aziridinium ion and undergoes a consecutive reaction with the starting amine to give a tetrasubstituted ethylenediamine. The rate constants as well as the activation energies of these reactions have been determined.

N-alkylation of ethylenediamine with alcohols catalyzed by CuO-NiO/γ-Al2O3

A simple method for N-alkylation of 1, 2-diaminoethane with different alcohols in a fixed-bed reactor using cheap CuO-NiO/γ-Al2O 3 as the catalyst has been developed. The present catalytic system was applicable in the N-alkylation of 1, 2-diaminoethane with both primary and secondary alcohols. Mono-N-alkylation of 1, 2-diaminoethane with low-carbon alcohols resulted in high yields; the yields of tetra-N-alkylation of 1, 2-diaminoethane with low-carbon alcohols declined markedly with the increase of the molecular volume of alcohols.

Reactions of (Et2NCH2CH2NEt 2)·H2SiCl2 with selected diorganometallic reagents of magnesium and lithium

Addition of the THF-insoluble di-Grignard reagent from 2,2′-dibromo- 4,4′-tert-butylbiphenyl (1) to a solution of [(teeda)·H 2SiCl2] in CH2Cl2/THF produced 2,7-di-tert-butyl-9H-9-silafluorene (3) in isolated, recrystallized yields of 2O, when reacted with [(teeda)·H2SiCl2] in CH2Cl 2/Et2O, gave similar yields of 5,10-dihydro-2,5,8- trimethylphenazasiline (4). In the absence of CH2Cl2 the major product produced from 1 was the spirocycle 2,2′,7,7′-tetra- tert-butyl-9,9′-spirobi[9H-9-silafluorene] both in a solvent-free form (5′) and as an ethanol solvate (5), both of which were crystallographically characterized. The spirocycle 2,2′,5,5′,8, 8′-hexamethyl-5,10-dihydro-10,10-spirobiphenazasiline (6) was formed from the reaction of the dilithio reagent of 2 in the absence of CH 2Cl2.