Oxido with rearrangement

Thus, a-sulfinyl lithium carbanion of 1-chloroethyl p-tolyl sulfoxide was reacted with 1,4-cyclohexanedione mono ethylene ketal (195) to afford the adduct (196) in quantitative yield. The adduct was treated with ferf-butylmagnesium chloride (magnesium alkoxide was initially formed) followed by isopropylmagnesium chloride to result in the formation of magnesium /3-oxido carbenoid 197. The /3-oxido carbenoid rearrangement then takes place to give one-carbon expanded magnesium enolate 198. Finally, an electrophile was... 

The /3-oxido carbenoid rearrangement then took place to give one-carbon expanded magnesium enolate having a chlorine atom (217), which was treated with water to afford a-chloroketone (218) in moderate yield. Unfortunately, this method could not be applied to larger cycloalkanones and acyclic ketones. Application of this method to aldehydes gave chloromethyl aryl ketones and chloromethyl alkyl ketones in moderate yields. ... 

Hydroxyamino)benzodiazepine (90) is acylated on oxygen upon reaction with acid chlorides (acetyl or benzoyl chloride) or isocyanates (methyl isocyanate) in the cold. On heating with acetic anhydride at 100°C, there is an oxido-reductive rearrangement to give the 3-acetoxy-2-methylamino derivative (91) (Scheme 14). This is considered to proceed by isomerization of the nitronium ion formed by cleavage of the N—O bond to the 3-carbonium ion which is trapped by the nucleophile (acetate) <80AP(313)926>. A similar mechanism is used to explain the formation of the 3-(l-imidazolyl) derivative (92) on reaction of (90) with carbonyl diimidazole. 

Aldehydes from oxido compounds with rearrangement... 

Potassium hydroxide methanol a-Hydroxyketones from l-acoxy-l,2-oxido compounds with rearrangement... 

Similar observations led Bernstein and co-workers" to assign structure (108a) to the rearrangement product of 5a,6a-oxido-3)5,17a-dihydroxy-6j5-methylpregnan-20-one 17-acetate (106) with anhydrous hydrogen fluoride or... 

In order to avoid acid-catalyzed rearrangements of 1,6-oxido-[10]annulene it is recommended that the distillation flask be treated with a base before use. 

In constrat to a-halo-/3-ketosulfoxides, I-chloroalkyl aryl sulfoxides react with Grignard reagents to give /3-oxido carbenoids. The rearrangement of these intermediates leads... 

The photochemical rearrangement of a -epoxyketones to / -diketones has been studied further. Results with 3-oxo-4,5-oxido-steroids indicate P — a alkyl shifts to be subject to stereoelectronic control, providing selectivity of the migrating group and stereospecificity of the rearrangement. The selective isomerizations of the epoxy-enone (48a)—> (49) at —65 °C and of (48b)— (50) plus (51) at 20 °C support such a hypothesis. Indeed, at higher temperatures even (48a) can be converted into (51), presumably via an additional radical intermediary step. ... 

Strained -oxidoalkyl i enyl selenoxides, such as l-oxido-l-(r-phenylsdenoxyalkyl)cyclopropanes, derived from oxaspiropentanes with tetraalkyl-substituted oxirane rings, and l-(r-hydroxyalkyl)-l-selenoxycyclobutanes, - obtained on oxidation of the corresponding selenides or on reaction of a-li-thioalkyl selenoxides with cyclobutenones, possess a high propensity to rearrange to cyclobutanones... 

A soln. of cyclooctene oxide in benzene passed at 180 with the aid of Ng through a column packed with Li-orthophosphate pellets 3-hydroxycyclooctene. Y 70%. - Li-diethylamide causes mostly rearrangement to 2-hydroxybicyclo[3.3.0]-octane. M. N. Sheng, Synthesis 1972, 194 allyl alcohol from propylene oxide s. A. G. Polkovnikova, N. S. Usacheva, and A. E. Folomeeva, Khim. Prom. 49, 325 (1973) C. A. 79, 31412 2-ethylenealcohols preferably with Li-di-n-propylamide or Li-di-n-butylamide s. C. L. Kissel and B. Rickborn, J. Org. Chem. 37, 2060 (1972) by thermal rearrangement without added acids or bases s. R. J. Anderson et al., Am. Soc. 94, 5379 (1972) basic rearrangements of oxido compds., review s. V. N. Yandovskii and B. A. Ershov, Russ. Chem. Rev. 41, 403 (1972) (Eng. transl.). 

Ketones from oxido compds. with skeletal rearrangement... 

Ethylmagnesium bromide hydrogen chloride 2,3>Oxido-l,4>diketones from 1,4-diketones with trans-cis-rearrangement... 

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