Staudinger-aza-Wittig process

Quinazolines have also been prepared by the reaction of a polystyrene-bound phosphoranimine and isocyanates, followed by an intramolecular cyclization of the carbodiimide intermediate 4-Ferrocenylidene-l-aminoimidazolone derivatives have been obtained from p-ferrocenyl-a-azidoacrylates and isocyanates followed by condensation of the resulting carbodiimidoester with hydrazines " In a Staudinger/ aza-Wittig process and in the presence of PPh3, bimetallic ferrocenyl oxazole derivatives (23) - (26) have been formed by the reaction of a-... 

Ph3P in anhydrous THF effected thiazoline formation by the intramolecular Staudinger-aza-Wittig process to deliver C35 0-TBS ether 110. Completion of the total synthesis of the cyclodepsipeptide apratoxin A (111) from thiazoline 110 would have required only two further operations amide formation between proUne amine and /so-leucine carboxyl-ate residues and removal of the C35 0-TBS-protecling group (Scheme 15.23). 

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