Influence of Alkoxides and the Dimetalation of Some Alkylaryl Hydrocarbons¹

Alkyl and Aryl Derivatives of the Alkali Metals: Strong Bases and Reactive Nucleophiles. 2. Wilhelm Schlenk’s Organoalkali-Metal Chemistry. The Metal Displacement and the Transmetalation Reactions. Metalation of Weakly Acidic Hydrocarbons. Superbases

“…This was a very potent polymerization initiator (“ALFIN catalyst”) . However, more pertinent to the present discussion, Morton also found that addition of sodium isopropoxide or, better, potassium isopropoxide, to a suspension of n -amylsodium in alkane medium increased the already high bascity of n -amylsodium: more rapid reactions gave higher yields of metalation product . The most spectacular observation made was that n -C 5 H 11 Na/ i PrONa could metalate ethylene directly to give vinylsodium .…”

Alkyl and Aryl Derivatives of the Alkali Metals: Useful Synthetic Reagents as Strong Bases and Potent Nucleophiles. 1. Conversion of Organic Halides to Organoalkali-Metal Compounds

“…2:1 molar mixture of n-amylsodium and sodium 2-methyl-2-heptoxide was used rather than n-amylsodium alone. 95 The presence of sodium and, especially, potassium alkoxides increased the coupling product yields obtained in some Wurtz reactions. 96 Thus, the reaction of n-amylsodium with n-amyl chloride in toluene, which generated benzylsodium as the active reagent by initial rapid metalation of toluene, gave n-hexylbenzene (16%) and n-decane (25%).…”

“…Preparative details for the synthesis of n -butyllithium in 80−85% yield in diethyl ether at −10 °C were published by Gilman some years later 2 Synthesis of Organolithium Reagents by the Reaction of Organic Halides with Metal Lithium (in Fine Pieces) in Diethyl Ether a organic halide, RXRLi yield, %organic halide, RXRLi yield, % 1,4,2-(CH 3 )[(CH 3 ) 2 CH]C 6 H 3 Br 74 CH 3 I 74 o -CH 3 OC 6 H 4 Br 84 n -C 4 H 9 Cl 76 p -CH 3 OC 6 H 4 Br 75 n -C 4 H 9 Br 59 o -C 2 H 5 OC 6 H 4 Br 73 n -C 11 H 12 Br 39 p -C 2 H 5 OC 6 H 4 Br 77 cyclo-C 6 H 11 Cl 23 p -(CH 3 ) 2 NC 6 H 4 Br 95 C 6 H 5 Cl 35 α-C 10 H 7 Br 79 C 6 H 5 Br 95 β-C 10 H 7 Br 74 C 6 H 5 I 80 p -C 6 H 5 C 6 H 4 Br 77 o -CH 3 C 6 H 4 Br 93 m -CH 3 C 6 H 4 Br 85 p -CH 3 C 6 H 4 Br 98 a From ref b. Conditions: 0.05 mol of RX in 15 mL of Et 2 O added to 0.11 mol of lithium cut into fine pieces in 15 mL of Et 2 O over 30−35 min, mild heating (if necessary) applied to maintain a gentle reflux, stirring and refluxing maintained for 1 h. …”

“… a From ref b. Conditions: 0.05 mol of RX in 15 mL of Et 2 O added to 0.11 mol of lithium cut into fine pieces in 15 mL of Et 2 O over 30−35 min, mild heating (if necessary) applied to maintain a gentle reflux, stirring and refluxing maintained for 1 h. …”

“…Also, Morton and Eisenmann found that the metalation of alkylbenzenes, RC 6 H 5 (R = Me 2 CH, Me 3 C, n -C 4 H 9 ), was considerably accelerated when a ca. 2:1 molar mixture of n -amylsodium and sodium 2-methyl-2-heptoxide was used rather than n -amylsodium alone …”