Dichloromaleic acid anhydride, reaction

The heterocyclic acylphosphines (52) and (53) have been prepared by the reaction of phenylbis(trimethylsilyl)phosphine with the acid chlorides derived from phthalic and diphenic acids. The reaction of 2,3-dichloromaleic anhydride or thioanhydride with phenylbis(trimethylsilyl)phosphine gives derivatives of the 1,4-dihydro-p-diphosphorin system (54).45... 

One exception to the use of primary phosphines is in the reported syntheses of the catASium M dass of ligands 20 [46-49]. In one report, reaction of the cyclic sulfate with P(TMS)3 yields the TMS-protected secondary phospholane, which could then be reacted with the appropriate 1,2-dichloro spedes [46]. An alternative procedure to the same intermediate involves preparation of 1-phenyl-phospholane via the bismesylate, subsequent lithium-induced P-Ph deavage, and quenching with TMSC1 [49]. The ligand based on 2,3-dichloromaleic anhydride (20a originally referred to as MalPHOS [46]) has been shown to be effective for the chiral reduction of a- and /1-deliydroarnino acid derivatives and itaconate derivatives. 

The reaction between a phenol and dichloromaleic anhydride catalyzed by aluminum chloride gives an aroylacrylic acid, which cyclizes to a chromone on treatment with a weak base (79SC129). However, at higher temperatures an indenone is formed. 

In another reaction, conducted also in acetic acid, methylmaleic hydrazide (21, R = R2 = H, Ri = Me) has been isolated as the only product.If, however, a mixture of acetic acid and methanol were employed as solvent, citraconic and related anhydrides formed linear dihydrazides of type 23. A new type of reaction product, a A,A -biimide (26), has been established to result when dimethyl- or dichloromaleic anhydride were allowed to react with hydrazine in acetic acid with cooling. 

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