Diazomethyl anion

The second step of (4-25) refers to the acidity of diazomethane, i.e., to its deprotonation to the diazomethyl anion. Diazoalkyl anions were obtained in solution by reaction of a carbanion with nitrous oxide (4-26) (Bierbaum et al., 1977). 

It would appear today, however, that the acid-base equilibrium of diazomethane with its anion is better known in the gas-phase than in solution The same group (DePuy et al., 1989) investigated reactions of the diazomethyl anion with CS2, COS, CO2, SO2, and with a series of a,)ff-unsaturated aldehydes and ketones — all in the gas phase using a flowing afterglow apparatus (DePuy and Bierbaum, 1981) and selected ion flow tube techniques (Van Doren et al., 1987). 

White phosphorus, P4, reacts with TMSC(Li)N2 to give 1,2,3,4-diazadiphospholide anion, which results from a formal [3 + 2] cycloaddition between [P=P] and the diazomethyl anion. The protonation of the phospholide anion with TFA affords 7H-1,2,3,4-diazadiphosphole (eq 33). ... 

The scope of the rearrangement reaction whereby azido-l,2,3-triazolide ion (66) is converted to the (diazomethyl)tetrazolide ion (68) has been studied. Where R = H, substituted phenyl, Me, and C02Me the reaction proceeds at a rate which is largely independent of substituent extensive decomposition is observed where R = COMe, COAr, and CN. PM3 calculations used to explore the energy profile of the reaction pathway indicate that the order of anion stability is (67) < (66) < (68) and that the rearrangement is of the type (66) (67) (68) for which 2 and k i ki. 

A mechanism (Scheme 1) has been considered by Regitz and Anschutz for the interaction of diethoxyphosphinylacetaldehyde and / -toluenesulphonylazide which depends on addition of azide to the enolate anion followed by an elimination which, in this case, yields diethyl (diazomethyl)phosphonate. 

OSiMe3]. Acid-catalysed decomposition of p,y-unsaturated diazomethyl ketones has been developed as a cyclopentanone annelation procedure, thus (322) gave 10,10-dimethylbicyclo[5,3,0]dec-7-en-9-one (50—69%) when treated with BFa-etherate then aqueous HCl. The enolate anion of 2-methoxycarbonylcycloheptanone reacts with 1-phenylthiocyclopropyltriphenylphosphonium fluoroborate to give the Wittig product (323) which was hydrolysed to the corresponding keto-acid (90% overall). 

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