Rearrangement Phenyllithium

Similarly, thiazole reacts at —60°C with phenyllithium affording thiazol-2-yllithium (156) (13, 437). As in the case of the Grignard derivative, thiazolyllithium does not rearrange under heating as does the adduct of pyridine and butyllithium (438). 

The reaction of phenyllithium and alfyl chloride labeled with C reveals that allylic rearrangement occurs. About three-fourths of the product results from bond formation at C-3 rather than C-1. This can be accounted for by a cyclic transition state. ... 

Cyclobutylidenecarbene, generated by base-promoted reaction between cyclobutanone and diethyl (diazomethyl)phosphonate at (CC (Method A),1,2 or by treatment of dibro-momethylenecyclobutane with phenyllithium at —40 to +20 C (Method B),3 4 rearranged to a transient entity, thought to be cyclopentyne3 6 or a lumomer of cyclopentyne.7,8 This entity underwent stereospecific cis addition to both (Z)- and ( )-l-melhoxypropene,2 and (Z)- and ( )-but-2-ene,4 and prefers 1,2- over 1,4-addition with buta-1,3-diene.4 These and other examples are collected below. 

As mentioned in Section IV,B,2, thiabenzenes can rearrange to 4H-thiopyrans275,277 280 342 or mixtures of both 2H and AH isomers39,277,280-282 thermally,275,277 280 281,342 with acids-,281 or photochemically.281,282 A detailed discussion concerning the changes in the structure of the starting thiabenzenes during their interaction with phenyllithium is available.343... 

Phenyllithium also occupies a place in epoxide literature in connexion with a curious rearrangement first noted by Bergmann and Wolff,1 and later elucidated by Kohler and co-workers.us.sm.mi Treatment of benzalacetophenone oxide and certain derivatives with 1 molar equivalent of phenyllithium in the cold gives the corresponding a 3-epoxy alcohol in which addition has occurred preferentially at tlie carbonyl junction. Further treatment of this product with excess phenyllithium at room temperature causes rupture of a C—C bond. The product ultimately isolated is triphenylcorbino), which presumably forms from the initially-generated benzophenone, as shown in Kq. (807). PhenyJaoetaldehyde polymerizes too rapidly under these conditions to allow its isolation, but other evidenoe indicates that H is formed in all likelihood at the same time as the benzophenone. 

Although, in principle, any arsonium ylide could be prepared via the slat method as demonstrated above, attempts to prepare a ylide from dimethyldibenzylarsonium salt (4) with ethereal phenyllithium failed. The product of the reaction after quenching with water was stilbene (5). Apparently, a Stevens rearrangement occurred during the reaction (101). 

Such a rearrangement was observed to occur as a side reaction when iV-alkylamino-m-chlorophenyldimethylsilane is reacted with phenyllithium. m-Chlorophenyldimethylsi-loxane was obtained in low yield after hydrolysis.251... 

Triethylallylammonium chloride undergoes the Stevens rearrangement on treatment with phenyllithium.329 2-Phenyl-3,3-dimethyl-indoline is rearranged to 2-phenyl-2,3-dimethylindoline by the action of phosphoric acid.330... 

Phenyllithium (and lithiophosphites) also bring with them sufficient stabilisation of the organolithium for Brook rearrangement to occur readily.40 With acylsilane 49, intramolecular Michael addition leads to cyclic structures 50. 

During an investigation of a Stevens rearrangement, a conversion of the spirocyclic ammonium salt 148 into the tetracyclic 149 was found to occur on treatment with phenyllithium (54LA(589)55). 

The Stevens rearrangement of 1,3,4-trimethyl-1 -p- chloro benzyl- 3-piperideinium chloride (148) with phenyllithium in ether was found to give three products, namely, 15% 1,3,4-trimethyl-2-p-chIorobenzyl-3-piperideine (149), 1,3,4-trimethyl-4-p-chlorobenzyl-2-piperideine... 

An alternative approach to 2-benzyl-l,3,4-trialkyltetrahydropyridines (73) from the phenyllithium-induced Stevens rearrangement of the corresponding 1-benzyl-l-methyltetrahydropyridinium salt was introduced by Fry and May.(35) Rearrangement occurs predominantly to the 2-position and cyclization of 73 is effected under standard conditions. 

The first preparation of a stibonium ylide was probably achieved in 1953. When dibenzyldimethylstibonium bromide was treated with phenyllithium, the product obtained was dimethyl(l,2-diphenylethyl)stibine which could arise from a Stephens rearrangement of the expected ylide (see equation 45) addition of the phenyllithium first of all afforded a yellow colour which rapidly disappeared. 

In 1960 triphenylstibonium methylide, Ph3Sb=CH2, was obtained in solution by treating methyltriphenylstibonium tetrafluoroborate with phenyllithium in ether When the resultant solution was treated with benzophenone, acid work-up provided high yields of triphenylstibine and diphenylacetaldehyde ", and it has been suggested that the latter product arose by acid-induced rearrangement of initially formed 1,1-diphenylethy-lene oxide, the most likely product from reaction of this reactive ylide with a carbonyl compound. 

A new approach to the morphine skeleton was demonstrated by the total synthesis of (+)-desoxycodeine-D by C.-Y. Cheng and co-workers." " The key step was the formation of the B ring by the Stevens rearrangement of a tetrahydroisoquinoline-derived quaternary ammonium salt upon treatment with phenyllithium. 

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