Alkenes phthalimides

Imides can also add to alkenes or alkynes. Ethyl 2-propynoate reacted with phthalimide, in the presence of a palladium catalyst, to give ethyl 2-phthalimido-2-propenoate. ... 

Sulfur dichloride is difficult to handle it disproportionates readily, has an unpleasant odor, and tends to introduce extra, unwanted chlorine atoms. Several reagents have been developed, especially by Harpp and co-workers, in which these undesirable features have been modified or eliminated. Succinimide-N-sulfenyl chloride (28) and phthalimide-N-sulfenyl chloride (29) are both stable crystalline compounds which undergo many of the reactions of the sulfur dichloride itself. They can, for example, be used in a facile, high yield synthesis of thiiranes from alkenes.33... 

In einer Zweistufen-Variante der Schweizer-Reaktionlassen sich l-Amino-2-alkene mit fast ausschlieBlicher oder liberwiegender (E)-Struktur herstellen, indem man Aldehyde (Benzaldehyde, Zimtaldehyd, Furfural) in Tetrahydrofuran mit Ethenyl-tributyl-phospho-nium-bromid, Phthalimid und Natrium-hydrid (-fPhthalimid-natrium) umsetzt und das so erhaltene, N-substituierte Phthalimid mit Hydrazin spaltet oder mittels Natriumsulfid/ Wasser in Phthalsaure-monoamide uberfuhrt und diese mittels waBriger Oxalsaure spaltet1. Bei Zusatz von Lithiumbromid in der 1. Stufe erhalt man uberwiegend die (Z)-Iso-meren. 

Furthermore, electrophilic anti addition of /V-(phenylselanyl)phthalimide in the presence of triethylamine tris(hydrogen fluoride) has been investigated using alkenes (Table 14)216 and alkynes.217... 

The electrophilic anti addition of benzeneselenenyl fluoride to C = C bonds has been performed in a one-pot reaction with, /V-(phenylselanyl)phthalimide/triethylamine tris(hydrogen fluoride) using disubstituted alkynes to give a-fluoro-/T(phenylselanyl)alkenes 4.217... 

Thiiranes can be formed directly and stereospecifically from 1,2-disubstituted alkenes by addition of trimethylsilylsulfenyl bromide, formed at -78 C from reaction of bromine with bis(trimethylsilyl) sulfide (Scheme 7).12 A two-step synthesis of thiiranes can be achieved by addition of succinimide-A/-sulfe-nyl chloride or phthalimide-A -sulfenyl chloride to alkenes followed by lithium aluminum hydride cleavage of the adducts (Scheme 8).13 Thiaheterocycles can also be formed by intramolecular electrophilic addition of sulfenyl chlorides to alkenes, e.g. as seen in Schemes 914 and 10.13 Related examples involving sulfur dichloride are shown in Schemes 1116 and 12.17 In the former case addition of sulfur dichloride to 1,5-cyclooctadiene affords a bicyclic dichloro sulfide via regio- and stereo-specific intramolecular addition of an intermediate sulfenyl chloride. Removal of chlorine by lithium aluminum hydride reduction affords 9-thiabicyclo[3.3.1]nonane, which can be further transformed into bicyclo[3.3.0]oct-1,5-ene.16... 

The first example of intermolecular Pd-catalysed aminoacetoxylation of alkenes, such as (52), with phthalimide as the nitrogen source and PhI(OAc)2 as the stoichiometric oxidant and source of acetate has been reported. The reaction is highly regio- and diastereo-selective mechanistic studies revealed that the reaction proceeds... 

A PET reaction between excess phthalimide (in equilibrium with its conjugate base) and an alkene led to a clean phthalimidation of nonactivated double bonds. Here, the singlet excited state of phthalimide acts as the oxidant and a radical ion pair is formed. The olefin cation radical is trapped by the phthalimide anion, and back electron transfer, followed by protonation, affords the photoaddition products [40], Protected phenethylamines are readily accessible in this way. This reaction has been carried out by using NaOH as the base it has been shown that the amounts (usually equimolar with the alkene) must be carefully chosen in order to avoid the undesired competition with [2 + 2] photocycloaddition. 

In addition, the phthalimide anion undergoes photoaddition with a wide variety of alkenes, providing a preparative method for the synthesis of [2]benzazepine-1,5-diones via a [2 + 2] cycloaddition followed by a thermal ring expansion (Scheme 9.46) [79]. 

Suau, R., Sanchez-Sanchez, C., Garcia-Segura, R., and Perez-Inestrosa, E. (2002) Photocycloaddition of phthalimide anion to alkenes. A highly efficient, convergent method for [2]benzazepme synthesis. European Journal of Organic Chemistry, 1903-1911. 

Phenylthiofluorination of alkenes can be carried out by using Ar-(phenylsulfanyl)phthalimide combined with hydrogen fluoride/pyrid example, the formation of 10. ... 

Phthalimides participate in a number of photo-induced electron-transfer processes. They have been found to react with alkenes with the formation in some cases of oxetanes, e.g. [140], and ring expansion products [141] (Scheme 32) (Mazzocchi et al., 1978a, 1979 Maruyama and Kubo, 1978a). The reaction can also be carried out intramolecularly (Maruyama et al., 1978 ... 

Machida et al., 1980a). When 1,1-diphenylethylene is used as the alkene and methanol is used as solvent, adducts such as [142] are produced which indicate that the reaction occurs by an electron-transfer process (Scheme 33) (Maruyama and Kubo, 1978b). Phthalimides also react with conjugated dienes to give ring expansion products (Mazzocchi et al., 1978b, 1977) only one of the... 

The stereoselective formation of /3-hydroxy selenides has also been reported 36 in the reaction of alkenes with, V-(phenylseleno)phthalimide or the succinimide derivative in aqueous acetonitrile or dichloromethane. The use of phenylselenenyl chloride under these conditions gives similar results (Table 5)37. 

Table 5. 2-(Phenylselcno)cycloalkanols or /8-(Phenylseleno)alkanols from Cyclo-alkencs or Alkenes and jV-(Phenylseleno)phthalimide or -succinimide or Phenylselenenyl Chloride36-38...

The thermally or photochemically activated addition of cyclic A-bromo imides to alkenes, particularly to cyclohexene, is inefficient, even when diastereoselective63-66,141. However, A-bromo phthalimide reacted readily with 2,3-dihydrofuran to give the regioisomers 2 and 3, and with 3,4-dihydro-2//-pyran to give 4 regioselectively in satisfactory yield141. The franv-diastereomers were formed predominantly, especially in the case of the six-membered cyclic compound 4. 

The phenylthiofluorination of alkynes using (V-(phenylsulfanyl)phthalimide and hydrogen fluo-ride/ pyridine yields the substituted l-fluoro-2-(phenylsulfanyl)alkenes 4.714... 

Other amidoselenenylation reactions have been described. Salazar [50] reported that the carbamatoselenenylation of alkenes can be effected using hT-(phenylseleno)phthalimide, in the presence of tetrafluoboric acid, and ethyl carbamate as the nucleophile. The reaction is a stereospecific anti addition and works well with monosubstituted and 1,2-disubstituted alkenes. In the case of monosubstituted alkenes mixtures of regioisomers were obtained. 

One of the most important addition reactions which involves nitrogen nucleophiles is the azidoselenenylation of alkenes because both the azido and the phenylseleno group can give rise to several useful transformations. These compounds were first prepared by Krief from the reaction of alkenes with PhSeBr followed by sodium azide in DMF [54]. Direct azidoselenenylation of alkenes can be effected with PhSeCl and sodium azide in DMSO [55]. Under these conditions the reaction is stereospecific but it is not regiospecific. Similarly, the reaction of exocyclic alkenes with N-(phenylseleno)phthalimide and azido-trimethylsilane in methylene chloride (Scheme 11) gives rise to a 1 1 mixture of the regioisomers 67 and 68 [56]. 

Interest in the photochemistry of the phthalimide systems has continued. The phthalimide derivatives (316) are phot ochemically reactive and on irradiation in acetone yields the cyclized products (317). The reaction involves hydrogen abstraction to yield the biradical (318) which subsequently bonds to afford the observed products. A recent study has examined the behaviour of the anion (319) in an attempt to reduce electron transfer processes. In t-butanol irradiation affords the solvent addition product (320) as the principal product presumably by a free radical path. Minor products (321) and (322) are also formed but are probably artefacts of the work-up procedure. Irradiation of (319) in methanol with added cyclohexene follows a different reaction path. In this system the reaction with methanol is minor while the dominant reaction is addition of the alkene to afford the adduct (323) in 20 % yield. The Dewar benzene derivative (324) is photocheraically unstable and irradiation affords t etramet hyl cyclobutadiene. ... 

The photoaddition of phthalimides and related dicarbox-imides to alkenes has been the subject of detailed study over the years. In the presence of added methanol, the photoreactions of dicarboximides with alkenes also result in the formation of methanol-incorporated products. The efficiency of alcohol trapping by the N-methylphthalimide-alkene radical ion pair, which is involved in... 

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