Donald J. Peterson

Phosphinomethyllithium compounds IV. An improved method of preparation and some synthetic applications

Abstract Three methylphosphines have been found to undergo rapid reactions with a 1:1 complex of n-butyllithium and tetramethylethylenediamine to give moderate to high yields of phosphinomethyllithium compounds. This method of preparation enjoys several advantages over the known method. The utility of phosphinomethyllithium compounds as intermediates in the synthesis of carbon-functionally substituted organophosphines has been demonstrated by the conversion of (diphenylphosphino) methyllithium to [(C 6 H 5 ) 2 P] 2 CH 2 , (C 6 H 5 ) 2 P(S) CH 2 CO 2 H, (C 6 H 5 2 P(S) CH 2 D, (C 6 H 5 ) 2 P(S)CH 2 C(OH)(C 6 H 5 , and (C 6 H 5 ) 2 (CH 3 )P + CH 2 C(OH)(C 6 H 5 ) 2 I − .

Functionally-substituted N,N-dialkylaminomethyllithium compounds

A variety of functionally-substituted N-alkyl-N-methylaminomethyllithium compounds, CH3 (R)NCH2 Li, have been prepared in moderate to high yields via transmetalation reactions between the appropriate (N-alkyl-N-methylaminomethyl)tributyltin compounds and n-butyllithium. Also, bis(N-lithiomethyl)methylamine was obtained by this synthetic method. N-Benzyl-Nmethylaminomethyllithium (I) was found to readily undergo a 1,2-anionic rearrangement to give N-lithio-N-methyl-β-phenethylarnine, a reaction analogous to the “Wittig rearrangement” of metalated ethers. A synthetically useful nucleophilic methylaminomethylation of an aldehyde [i.e., RCHO to RCH(OH)CH2NHCH3] has been effected through the use of (I).

Electrophilically-induced cyclodestannylation reactions

Abstract A variety of cyclopropylcarbinyl compounds has been prepared by cyclodestannylation reaction of alk-3-en-yltin compounds. the initial stage of the cyclodestannylation reactions is thought to involve addition of electrophiles to the double bonds of the alk-3-en-1-yltin compounds to form electron deficient carbon atoms γ to tin. These incipient carbonium ions the electrophilically induce heterolytic fragmentations of the carbon-tin σ bonds (electrophilic displacement of R 3 Sn + ) with concurrent ring formation. Cyclopropylmethoxy derivatives were similarly obtained from thermal and Lewis acid catalyzed cyclodestannylation reactions of 3,4-epoxybutyltri-n-butyltin.

Preparation and reactions of some sulfur-substituted tetraorganotin compounds

Abstract Some sulfur-substituted organotin compounds, R3SnCH2X, where X = SCH3, SO2C4H9-n, SO2C6H5, S+(CH3)2Z−, etc., have been synthesized and studied with regard to their solvolytic and “organometallic-like” behavior. Reactions of the organotin compounds with substrates known to be reactive toward classical organometallic compounds tend to place these materials by comparison on the lower end of the reactivity scale.