Li alkylation

Bunawerke Huls GmbH Europe Buna Li—alkyl... 

Ehestone Synthetic Rubber North America Diene Li—alkyl... 

Polysar North America Vinjl butadiene rubber T aktene Li—alkyl... 

Addition of TCS 14 to Cu-catalyzed 1,4-additions of Grignard reagents of Li alkyls to a/yS-unsaturated carbonyl compounds has recently been repeatedly reviewed [42-44 a] and is thus not treated here. 

One main driver was to increase the processing temperature for this class of metallation reactions more towards ambient. Typically, Li alkylations are conducted under cryogenic conditions (e.g. at -60 °C) [83]. Further motivation came from aiming at increasing the yield reducing investment and operating costs. 

Organic synthesis 70 [OS 70] Li alkylation of ketones yielding chiral alcohols... 

Bunawerke Hbls GmbH Europe Buna Li— alkyl... 

Li Alkyls react with siloxene to form a dark product of the composition338)... 

At the onset potential for reduction of about 1.5 V (Li/Li+), alkyl carbonate-based solvents, such as PC, EC, and DMC, are reduced in the presence of Li ions on nonactive electrodes to R0C02Li compounds. The most probable compounds formed in the case of PC and EC are propylene and ethylene lithium dicarbonates, respectively. The mecha-... 

T < 600 K, it seems quite plausible that ethylene oxide is derived from the thermal decomposition of a lithium alkoxide (most probable propoxide) produced by the (lower temperature) release of C02 from the corresponding Li alkyl carbonate. In fact, the fragments observed for the thermal decomposition of BuOLi were consistent with at least two different epoxides. 

Mn1" alkyls appear to be particularly prone to disproportionation.197 Attempts to prepare them from [Mn(acac)3] and Li alkyls in the presence of phosphines give transient colour changes at low temperatures which appear to be the Mn1" species, but only Mn" and Mnlv alkyls (q.v.) have been isolated from the solutions. An interesting report,576 which has not yet been confirmed, describes... 

Reaction of Li alkyls with (1) gives acyl anions, which upon alkylation form Fischer-Type Carbene complexes (see Fischer-type Carbene Complexes) (Scheme 6). 

The reaction of [LMn(CO)s] (L = CO, PRj, P(OR)3) with Li alkyls and organomagnesium halides gives the corresponding neutral acyl complex LMn(CO)4(COR). Where L = PRj or PCORj) only cis-addition products can be isolated. The reactions of this cationic species are instantaneous and faster than the isoelectronic LMfCO), (M = Cr, Mo, W) complexes whose rates are slow enough to be measured by conventional kinetic techniques . ... 

---