Cyclopropylphosphonium salts reactions

Cyclopropylphosphonium salts are produced, together with the phosphonium salts (76), in reactions of ylides with vinylsulphonium salts... 

More synthetic routes to the l-(hydroxymethyl)pyrrolizidines have been reported. Two groups3,4 have published the same route to ( )-isoretronecanol (3) (Scheme 1). The key step is the nucleophilic attack of succinimide anion on the cyclopropylphosphonium salt (1), followed by intramolecular Wittig reaction to generate the unsaturated pyrrolizidinone ester (2). Catalytic reduction and reduction with a hydride yielded ( )-isoretronecanol (3). Flitsch and Wernsmann achieved a higher overall yield (62%) by carrying out the first step in boiling xylene.3... 

This A -phosphane has been developed as a suitable building block in organic chemistry (see Section 5.13.1.). However, some higher homologues of the cyclopropylphosphonium salts have been synthesized. (3-Bromo-2-methylpropyl)triphenylphosphonium bromide was similarly converted into (2-methylcyclopropyl)phosphonium bromide upon reaction with sodium ethoxide in ethanol. ... 

Cyclopropylphosphonium salts are also equivalents of 1,3-diyls3,4. In this reaction the formal zwitterion is attacked by an electron-rich enolate. Typical applications are the reaction of cyclopropylphosphonium sails with ot-oxocycloalkanecarbaldehydes to give spirocyclic systems, however, yields are low and diastereoselcctivity is only moderate4. 

Partially hydrogenated pyrrolizines are easily obtained in high yield from a reaction of imides with cyclopropylphosphonium salt (195). Pyrrolizine ester (197) was obtained from succinimide, in a reaction via (196) phthalimide gave the benzopyrrolizinone (198) <80TL4585,81TL719>. Compound (199) was obtained from succinimide with triphenylcyclopropylphosphonium tetrafluoroborate... 

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