Cyclohexene oxide, preparation

Hasebe, Y Tsuruta, T. Structural studies of poly(l,2-cyclohexene oxide) prepared with well-defined organozinc compounds. Makromol. Chem. 1987,188, 1403-1414. 

Cyclohexadiene has been prepared by dehydration of cyclohexen-3-ol,3 by pyrolysis at 540° of the diacetate of cyclohexane-1,2-diol,4 by dehydrobromination with quinoline of 3-hromocyclohexene,6 by treating the ethyl ether of cyclohexen-3-ol with potassium bisulfatc,6 7 by heating cyclohexene oxide with phthalic anhydride,8 by treating cyclohexane-1,2-diol with concentrated sulfuric acid,9 by treatment of 1,2-dibromocyclo-hexane with tributylamine,10 with sodium hydroxide in ethylene glycol,10 and with quinoline,6 and by treatment of 3,6-dibromo-cyclohexene with sodium.6... 

Conversion of epoxides into /3-hydroxy isocyanides—preparation of trans-2-isocyanocyclohexanol, using TMSCN to open cyclohexene oxide with trans stereochemistry, followed by KF/MeOH cleavage of the intermediate silyl ether. 

The simplest model compound is cyclohexene oxide III. Monomers IV, V and VII represent different aspects of the ester portion of I, while monomers VII and VIII reflect aspects of both the monomer I and the polymer which is formed by cationic ring-opening polymerization. Monomers IV-VII were prepared using a phase transfer catalyzed epoxidation based on the method of Venturello and D Aloisio (6) and employed previously in this laboratory (7). This method was not effective for the preparation of monomer VIII. In this specific case (equation 4), epoxidation using Oxone (potassium monoperoxysulfate) was employed. 

Cyclopentanecarboxaldehyde has been prepared by the procedure described above 2 3 by the reaction of aqueous nitric acid and mercuric nitrate with cyclohexene 6 by the action of magnesium bromide etherate 6 or thoria 7 on cyclohexene oxide by the dehydration of frarei-l, 2-cyclohexanediol over alumina mixed with glass helices 8 by the dehydration of divinyl glycol over alumina followed by reduction 9 by the reaction of cyclopentene with a solution of [HFe(CO)4] under a carbon monoxide atmosphere 10 and by the reaction of cyclopentadiene with dicobalt octacarbonyl under a hydrogen and carbon monoxide atmosphere.11... 

An early illustration of this ambiguous behavior was provided by Letsinger and coworkers in 1952 who wanted to prepare alkyl cyclohexanols by addition of n-butyllithium to cyclohexene oxide. Only 7% of the desired butyl cyclohexanol 4 was... 

Cyclohexene sulfide has been prepared by the action of thiourea, potassium thiocyanate, or ammonium thiocyanate on cyclohexene oxide.3 The method described above is a modification of that of Snyder, Stewart, and Ziegler.4... 

Petrov1854 prepared oyolic ketale from cyclohexene oxide (Kq. 076), but the stereochemistry of ring fusion was unfortunately not elucidated. Osonium-type intermediates are probably involved in them reactions, although their exact nature has not boon established. 

Racemic trans-2-phenylcyclohexanol has previously been prepared in a yield comparable to that realized in this procedure via copper-catalyzed phenyl Grignard addition to cyclohexene oxide using the more expensive copper(l) oxide.14... 

Cyclohexene oxide was first prepared by Brunei from o-iodo-cyclohexanol and solid potassium hydroxide.1 It has also been obtained by the oxidation of cyclohexene with benzoyl hydroperoxide.2... 

A material prepared by anchoring titanium(IV) on to the walls of a high-area, crystalline mesoporous silica (MCM41) has been used as an alkene epoxidation catalyst with alkyl hydroperoxides.204 The effect of replacing one of the three O—Si= groups to which the Ti(IV) is bound by an O—Ge= group is reported to lead to an increase in catalytic activity of up to 18% in die epoxidation of cyclohexene, although no explanation is provided and it is notable diat the selectivity towards the formation of cyclohexene oxide (versus cyclohexenol and cyclohexane-1,2-diol) was inferior to that with the non-modified system.205... 

Cleavage and resolution of epoxides.1 The aluminum reagent obtained by reaction of (R)-l with diethyl- or dimethylaluminum chloride shows slight reactivity in reactions with epoxides, but the ate complex (2), prepared from 1, (C2H5)2A1C1, and lithium butoxide, converts cyclohexene oxide into the chlorohydrin (3) in 40% ee. 

Treatment of 2-methoxycyclohexyl phenyl tellurium oxide, prepared from cyclohexene and phenyl tellurium tribromide in methanol followed by hydrolysis of the tellurium dibromide, with 3-chloroperoxybenzoic acid in methanol caused ring contraction with formation of the dimethyl acetal of cyclopentanecarbaldehyde1,2. 

Lithium amide deprotonation of epoxides is a convenient method for the preparation of allylic alcohols. Since the first deprotonation of an epoxide by a lithium amide performed by Cope and coworkers in 19585, this area has received much attention. The first asymmetric deprotonation was demonstrated by Whitesell and Felman in 19806. They enantioselectively rearranged me.vo-cpoxidcs to allylic alcohols for example, cyclohexene oxide 1 was reacted with chiral bases, e.g. (S,S) 3, in refluxing TFIF to yield optically active (/ )-2-cyclohexenol ((/ )-2) in 36% ee (Scheme 1). 

Alexakis and coworkers introduced the dilithiated chiral base 13 prepared from C2 symmetric fraws-diaminocyclohexane (Scheme 9)19. Amide 13 rearranged cyclohexene oxide (1) to allylic alcohol (R)-2 in 76% ee. Deprotonation in presence of 1.5 equiv. of LiCl in THF lowered the ee to 55%. When 13 was used to rearrange cyclooctene oxide in benzene, the allylic alcohol was obtained with an increased ee (87%). 

Free radical promoted cationic polymerization was successfully employed [77] for the preparation of new classes of liquid crystalline (LC) block copolymers comprising a semicrystalline block, poly(cyclohexene oxide), and LC block of different structures ... 

Asymmetric rearrangement of cyclohexene oxide. Cyclohexene oxide is rearranged to (S)-2-cyclohexene-l-ol in 92% ee by the chiral lithium amide (2) prepared from n-butyllithium and 1. Several related (S)-2-(disubstituted aminomethyOpyrrolidines prepared from (S)-proline are almost as stereoselective. ... 

The stereochemistry of the cyclohexene adduct was established as cis by comparison of the product with the authentic tnms-isomcr prepared by ring opening of cyclohexene oxide with tert-butylamine. Similarly, the products obtained from (Z)- and ( )-l-deuterio-l-decene were converted to diastereomeric oxazolidinones which were compared with the authentic diastereo-mers. Furthermore, different diastereomers were obtained from ( )- and (Z)-l-phenylpropene, It is therefore reasonable to assume complete syn addition for all alkenes. 

Among DASF derivatives examined, the compound 32 prepared from the diselenide 2 and cyclohexene oxide was revealed to be the best catalyst for this addition, giving up to 94 % ee. It is noteworthy that the sulfur (33) and tellurium analogues (34) of 32 also catalyzed the reaction to afford the alcohol, but with lower enantioselectivity (52% and 46% ee, respectively). Related compounds 35 and 36 do not act at all as a catalyst for the reaction, indicating that the presence of both hydroxyl and dimethylamino groups in 32 are indispensable to act as an efficient asymmetric catalyst. Typical results of enantioselective addition of diethylzinc to aldehydes other than benzaldehyde catalyzed by 32 are also summarized in Table 4. 

Epoxy compounds are prepared by heating halohydrins with strong caustic solutions and, where possible, distilling the product as it is formed. By this procedure, 3-chloro-2-butanol yields a mixture of cis-and frans-2,3-epoxybutane (90%), which can be readily separated by fractional distillation. Another example is the conversion of 2-chloro-cyclohexanol to cyclohexene oxide (73%). The reaction is included in an excellent discussion of the chemistry of ethylene and trimethylene oxides, ... 

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