Imides reaction with alkenes

A-halo electrophiles (TV-halo amines, A-halo amides and iV-halo imides) react with alkenes such as 1-hexene, cyclohexene and styrene in the presence of boron trifluoride to give halofluorides and A-halo adducts (equation 34)51. These types of reactions have been dis-... 

Walters, M. A. The anionic 1-aza-Cope rearrangement. Theoretical evidence for the intramolecular reaction of imide anions with alkenes. Tetrahedron Lett. 1995, 36, 7055-7056. 

A cross-linked and crystalline copoly(ester—imide) containing an alkene function was made by reaction of an unsaturated diacid chloride containing a cychc imido group with ethylene glycol at low temperature (27). 

Thione S-imides, such as the fluorenethione S-tosylimide (68), have been known for about ten years. Saito and co-workers93 have studied the cycloaddition reactions of 68 with compounds containing homonuclear and heteronuclear double bonds. In almost every case the imide (68) reacted as a 1,3-dipole with alkenes, for example, isothiazoline derivatives (such as 69) were formed and with azines the 1,2,4-thiadiazolidine derivatives (70) were produced.93... 

Sulfonyl imides (78) are, like sulfenes, prepared by dehydrohalogenation of the corresponding sulfonyl chlorides (79) (usually called sulfamoyl chlorides). Like sulfenes, they take part in [2 + 2] and [4 + 2] cycloaddition reactions with electron-rich alkenes or with 1,3-dienes, yielding 1,2-thia-zetidine 1,1-dioxides (80)104 or dihydro-1,2-thiazines (81),105 respectively. 

The reactions of 1,2,3-triazolium 1-imide (277) with a range of alkene and alkyne dipolarophiles give rise to a variety of new ring systems (Scheme 54). Compounds (276) and (278) are obtained from (277) by reaction with acrylonitrile and DMAD, respectively. These reactions are tandem 1,3-dipolar (endo) cycloadditions and sigmatropic rearrangements which are regio- and stereospecific <90JCS(Pl)2537>. Kinetic and mechanistic studies show that these reactions are dipole-HOMO controlled. The second-order rate constants are insensitive to solvent polarity, the reaction indicates... 

The addition to alkenes normally leads to unstable adducts that lose carbon dioxide under the reaction conditions. The intramolecular cycloaddition of the sydnone (30) takes place at room temperature, however (Equation (5)) and the cycloadduct (31) has been characterized <86HCA927>. The unstable species formed by the loss of carbon dioxide are also azomethine ylides. It is therefore possible for a second 1,3-dipolar addition to take place, as illustrated in Scheme 6 for the reaction of 3-phenylsydnone with Al-phenylmaleimide <86TL317,92JA8414>. This 2 1 addition has been used as the basis of a synthesis of polyimides. Imides of the type (32) were used as the dipolarophiles and their reaction with 3-phenylsydnone gave linear polymers <87MM726>. 

Numerous examples involving the preparation of tetrahydrothiophenes via [3 + 2] cycloaddition of thiocarbonyl ylides with electron-poor alkenes have been reported. Thiobenzophenone (5)-methylide (16), generated from 2,5-dihydro-1,3,4-thiadiazole (15) and analogous compounds, react with maleic anhydride, N-substituted maleic imide, maleates, fumarates, and fumaronitrile at —45°C (28,91,93,98,128,129). Similar reactions with adamantanethione (5)-methylide (52) and 2,2,4,4-tetramethyl-3-thioxocyclobutanone (5)-methylide (69) occur at ca. +45°C and, generally, the products of type 70 were obtained in high yield (36,94,97,130) (Scheme 5.25). Reaction with ( )- and (Z)-configured dipolaro-philes stereospecifically afford trans and cis configured adducts. 

Boron trifluoride and boron trifluoride-diethyl ether complex can be used as a source of fluoride ions in the presence of hypobromites and hypochlorites, e.g. methyl hypobromitc, tert-butyl hypobromite, methyl hypochlorite in carbon tetrachloride at 25 C. The addition of bromine monofluoride" and chlorine monofluoride" to various alkenes is accompanied by the formation of the corresponding alkoxybromides and alkoxychlorides which hinder the isolation of the halofluorinated products.57 jV-Bromo- and A -chloro-substiluted alkyl- and arylamines. -amides, and -imides, A -chloro-A,-methylamine, A -bromo-A -methylamine, A -chloro-A, /V-dimethylamine, A-bromo-A.A-dimethylamine, ACV-dichloro-A -methylamine, V,fV-dibromo-,V-mcthylaminc, A -bromosuccinimide, -V-chlorosuccinimide, Af-bromoacct-amide, A.A -dichlorourethane, can be used in the reaction instead of the hypohalites. The reactions with various alkenes conducted in dichloromethane at room temperature in the presence of boron trifluoride-diethyl ether complex produce bromofluoro and chlorofluoro addition products in 40-80 % yield. However, the reactions are complicated by the addition of A -halo-succinimides and Af.A-dichlorourcthane to the C = C bonds.58... 

Phosphoranes and phosphonate derived carbanions are also known to react with carbonyl compounds other than aldehydes and ketones, in reactions often referred to as non-classical Wittig reactions.35 Wittig olefination products can be obtained from the reaction of esters, anhydrides and some amides and imides with a range of stabilized and reactive phosphoranes. The reaction of stabilized and semi-stabilized phosphoranes with esters gives alkenes (Scheme 7). However, non-stabilized phosphoranes, such as methylenetriphenylphosphorane, tend to give P-keto phosphoranes on reaction with esters (Scheme 7)—the careful choice of the reaction conditions can also permit the preparation of the alkene in these reactions. 

In the reaction of alkenes with 4-substituted 3//-l,2,4-triazole-3,5(4//)-diones (13), the ene products, the diazetidines, the vinyl hydrazine derivatives, and rearrangement products, all derive from a common intermediate 14 which is thought to be an aziridinium imide or a 1,4-zwitter-ionic intermediate20 23. The intermediate can be trapped by methanol or acetone20 24. 

Succinimides and maleimides are accessible via processes analogous to those described for the corresponding anhydrides (see Section 9.4.3.3). Reactions of (COD)2Ni° with either alkenes or alkynes and isocyanates (i.e. heterocumulene analogs of CO2) give azametallacycles that upon carbonylation yield cyclic imides. With alkenes high yields of metallacycles are formed m both simple isocyanates as well as a,(o-diisocyanates. Carbonylation yields are variable, however (Scheme 18). Alkynes give lower metallacycle yields but high yields of die final imide (Scheme 19). ... 

Definitive evidence for the imidate intermediate was provided by Glikmans in 1966. Reaction between isobutene and acrylonitrile in anhydrous acetic acid containing 100% sulfuric acid allowed isolation and characterization of (7), which was readily hydrolyzed to the corresponding amide by dehydration of acetic acid (equation 1). Subsequent work by NorelF on reactions of alkenes with nitriles In anhydrous liquid hydrogen fluoride allowed isolation of imidoyl fluorides such as (8) for the first time. Such materials, obtained pure and fully characterized, react instantly with water to yield the amide (Scheme 4). 

Irradiation of cyclic aliphatic imides in the presence of alkenes affords the corresponding oxetanes in good yield83 "86 attempts to perform this reaction with the analogous open-chain imides have been unsuccessful87. 

A few examples have been described of Diels-Alder-like reactions with imides formally derived from sulfur trioxide.58 N-Sulfonylimides are quite reactive in a [2 + 2] fashion with alkenes, but their ability to generally act as dienophiles is yet to be established. Sulfonylimines do react with highly oxygenated dienes to give adducts after hydrolysis [Eq. (35)]. 

Imides prepared from a-aminoacid esters with an extractable y-proton (with respect to the phthalimide nitrogen as a) have been reported to furnish benz[c]diazepine-2,5-diones in a Norrish Type II process with retention of stereochemistry of the aminoacid asymmetric centre <92CB2467, 94T3627). Similar results are reported in the intramolecular cyclization of iV-alkyl succinimides, in contrast to the reaction of such compounds with alkenes in an intermolecular reaction, when the usual product is an oxetane <84CPB950,85MI901-02). 

A different approach using alkene derivatives involved allylic substitution reactions. Ethyl cyclohex-3-en-l-carboxylate (7.51) reacted with N-bromosuccin-imide to give 7.52.26 This allowed reaction with potassium phthalimide to give 7.53 in an overall yield of 41%. Catalytic hydrogenation and treatment with methylamine led to ds-3-aminocyclohexane-l-carboxylic acid, 7.22.26... 

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