A Convenient Laboratory Synthesis of Cyclobutanone

Synthesis of aryl cyclopropyl sulfides through copper-promoted S-cyclopropylation of thiophenols using cyclopropylboronic acid

“…This carbanion can then react with alkyl halides to provide the corresponding alkylated species 3 which can then be opened up by treatment with mercuric chloride to give the corresponding β-thioaryl ketone 4 [10]. Reacting 2 with epoxides results in the formation of the 1-(β-hydroxy)cyclopropyl aryl sulfides 5 [10] while reaction with formaldehydes [11] or aldehydes [12] affords 1-(arylthio)cyclopropylcarbinyl alcohols 6 . Treating 6 with Burgess reagent or with hydrobromic acid and zinc bromide leads to 1-arylthiocyclobutenes 7 [13] and 2-alkyl-substituted cyclobutanones 8 [11–12], respectively.…”

“…Reacting 2 with epoxides results in the formation of the 1-(β-hydroxy)cyclopropyl aryl sulfides 5 [10] while reaction with formaldehydes [11] or aldehydes [12] affords 1-(arylthio)cyclopropylcarbinyl alcohols 6 . Treating 6 with Burgess reagent or with hydrobromic acid and zinc bromide leads to 1-arylthiocyclobutenes 7 [13] and 2-alkyl-substituted cyclobutanones 8 [11–12], respectively. Treatment of 6 with hydrobromic acid and zinc bromide in the presence of a thiophenol provides the 1,1-di(arylthio)cyclobutane 9 which, upon reaction with copper(II) triflate and Hünig's base, rearranges to give the corresponding 2-(arylthio)-3-alkyl-1,3-butadiene 10 [12].…”

Lithiation of cyclopropyl and 2-methylcyclopropyl phenyl sulfides. Addition to carbonyl partners

“…* Determined by mass spectroscopy• Z (retention time 14.5 min) isomers: IR (CC14) 3080, 1580 cm NMR (CC14) 5 0.6-1.1 (m, 3 ), 1.18 (d, J = 3 Hz, 3 ), 1.8 (dt, J = 8 and 4 Hz, 0.8 H), 2.16 (m, 0.2 H), 7.05 (m, 5 H); MS m/e (rel %) 166 (5), 165 (11), 164(100), 149 (29), 135 (13), 131 ( 14), 116 (19), 110 (79), 91 (13), 77 (11), 66 (15), 65 (10). Caled for CmH12S:…”

Phenylthiocyclopropanea,c

“…In reactions where lithium phenylthiolate is formed (from cyclopropanone thioacetal or from 1,3-bis(phenylthio)propane), Copper(I) Iodide is used to scavenge the thiolate to improve yields of alkylated or hydroxyalkylated derivatives. 5, 31 Very high yields of β-hydroxyalkyl sulfides are obtained from saturated aldehydes and ketones, 1a,4-50 including Formaldehyde (80% yield) 26 and hindered or quite enolizable ketones such as tetramethylcyclohexanone (92% yield) 25,27 or trispiro[3.1.3.1.3.1]pentadecane-1,5,10-trione (54% yield) (eq 19). 44 The reaction occurs regioselectively on the carbonyl group of α,β-unsaturated aldehydes and ketones, 1a,25-51 including 2-hydroxymethylene ketones, 42 and proceeds stereoselectively with 4-t-butylcyclohexanone to produce almost exclusively the alcohol resulting from an equatorial attack (THF, 0 • C, 98% yield, 99:1 ratio of stereoisomers, eq 14).…”

“…32 The reaction has also been performed with p-Toluenesulfonic Acid in wet benzene 32 or tetralin. 26 These conditions require heating and are particularly useful for the adducts derived from saturated aldehydes. 32 They have been used for the synthesis of the parent cyclobutanone 26 (70-120 • C in the presence of Mercury(II) Chloride as a thiol trap).…”