Triorganolead halides

By rxn. of Me4Pb with Cl in EtOAc in presence of dry ice at -78° (1056), with BCI3 or B2CI4 at -78° to r. t. (II9I+), with SOgClg in CeHe (I66). By rxn. of (MegPbCOg with AcCl in CCI4, in 8 % yield (952)- 

RLi MegPbR R = MeCSC (20), C1C1C (I98O), PhaPCiC (2778), Me3SiN(CMe3) 

RNa - MesPbR R = EtC5C (20), polynuclear radical (27O3), MeO (673, I678), 

MeaPbCl-ONCsHs, IR and NMR spectra (23 0, 2 9 )-) [PbCeHi4ClN0]. MeaPbCl.ONCsEiMe-, from components in HaCCla or HCCI3, white cryst., dec. 

MeaPbCl.ONCsIltCl- i-, from components in HaCCla or HCCI3, white cryst., dec. 

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Enantioenriched a-alkoxyorganolead compounds have been prepared through lithiation of stannane precursors and trapping of the lithiated species with a triorganolead halide (equation 35)75. In the presence of TiCU, these plumbanes add to aldehydes to afford monoprotected syn- 1,2-diols. The use of BF3OEt2 as a Lewis acid promoter leads mainly to the anti adducts (Table 13)70. 

Besides the early preparation by Gilman173 of alkynyllead compounds using sodium acetylides and triorganolead halides, and the following modification of the method174 ... 

During the last 15 years much work has been done on plumbylalkynes. After Gilman (36) reported in 1938 the reactions of sodium acetylides with triorganolead halides, this procedure was developed by several groups (99,180, 269, 281). 

The Pb-Pb derivatives are by far the least numerous of the Group 14 singly bonded compounds due to the inherent wetikness of the metal-metal bonding. Chain compounds are limited to up to four linked lead units. The hexaorganodilead compounds represent the most studied class. Synthetic routes to access RjPb-PbRj include Wurtz coupling of triorganolead halides as well as reaction of lead(II) chloride with Grignards (Eq. (14.15)) [54]. 

Because of the lower metal-carbon and metal-hydrogen bond strength, organolead hydrides are particularly unstable species and represent the least stable of those of the group 14 elements. Triorganolead hydrides are obtained at low temperatures by reduction of the halides with LiAlH4 (equation 45), but they decompose at 0 °C. 

Triorganolead alkali compounds can be prepared from RjPbX (X = halide) with alkali metals in polar solvents, such as tetrahydrofuran (THF) or liq NH3 ... 

The reactivity of all triorganosilyl triorganolead oxides is so great, in fact, that they explode in the presence of aluminium chloride or carboxylic acid halides, with the departure of the lead. 

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