1-Lithiocyclopropyl phenyl sulphide

Reaction of 1-lithiocyclopropyl phenyl sulphide (123) with 4-t-butylcyclohexanone produces an adduct as a 99 1 mixture of two isomers. By analogy to organometallic addition to this ketone, the stereochemistry is assumed to result from equatorial attack. Treatment of the adduct with one equivalent of anhydrous stannic chloride followed by hydrolysis produces primarily cyclobutanones (equation 94) ... 

Treatment of l,3-bis(phenylthio)propane with two equivalents of butyl-lithium provides a simple synthesis of 1-lithiocyclopropyl phenyl sulphide, a versatile reagent for the preparation of cyclobutanones via ring expansion of its adducts with ketones (Scheme 20). ... 

The construction of a cyclopentanone unit through treatment of a ketone with 1-lithiocyclopropyl phenyl sulphide and pyrolysis of the vinylcyclopropane (10) so... 

General Methods.—Trost and his co-workers have extended their earlier studies of the synthesis of cyclopentanes based on thermolysis of vinylcyclopropanes, and shown that it is expedient to use the recently developed 1-lithiocyclopropyl phenyl sulphide (32) for the preparation of the appropriate vinylcyclopropane precursor. Thus addition of (32) to ketone (33), followed by dehydration of the intermediate hydroxy-sulphide with SOCI2, led to (34), which on thermolysis in the vapour phase at 350 °C, then hydrolysis, gave the cyclopentenone (35). An identical approach to cyclopentane annelation has been used by Miller in a synthesis of (36) from cyclopent-2-enone. 

Trost has published additional applications of a-lithiocyclopropyl phenyl sulphide, including an approach to spiro-sesquiterpenes, involving geminal alkylation, which utilizes a process that is formally the reversal of dithian-carbonyl addition(also see related studies by Marshall Synthetic applications of the highly nucleophilic methoxy-phenylthio-methyl-lithium PhSCH(Li)OMe and of the acyl anion equivalent methylthioacetic acid dianion RSCHCLOCOgLi (R = Me or Ph ) have also been described, as have synthetic procedures based on anions of a-alkylthio- or a-phenylthio-ketones and methylthiomethyl dithiocarbamates. ... 

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