Acid chlorides reactions with organometallic

Acid chlorides are prepared by standard methods and undergo the usual acid chloride reactions. They have found important applications as substrates in the syntheses of ketones by transition metal-catalyzed coupling reactions with organometallics (Section 6.02.5.5.14). Acid chlorides (424) are also good substrates for the preparation of ketones (425) using organomanganese(II) iodide, especially for the preparation of alkyl pyrimidinyl ketones <86ACS(B)764>. 

Another method that will produce a ketone from the Grignard reaction with an acid chloride changes the organometallic reagent from RMgX or RLi to one that is less reactive. In such a case, the organometallic reagent should react with the acid chloride but not with the ketone product. 

Bell and Hall have incorporated an organometallic unit into a crown by using the ferrocenyl unit as part of the ring or as a third strand. The unit is incorporated either as the 1,1 -diformylferrocene or the corresponding acid. In the former case, the bis-imine is prepared and reduced to give the saturated crown (see structure 24). In the latter case, the acid is converted into its corresponding chloride and thence into the diamide by reaction with a diamine. Diborane reduction affords the saturated amino-crown. Structure 24 could be prepared by either of these methods but the dialdehyde approach was reported to be poor compared to the amide approach which afforded the product in ca. 60% yield . 

The experimental conditions for the syntheses starting from acid chlorides of hydroxamic acids and from nitrile oxides are somewhat different. In the former case the other component of the reaction is organometallic, usually an organomagnesium derivative of an acetylene or, less frequently, a sodium enolate of a /8-diketone. Nitrile oxides condense directly with unsaturated compounds. 

Reaction of Acid Chlorides with Organometallic Reagents Grignard reagents react with acid chlorides to yield tertiary alcohols in which two of the substituents are the same. 

The formation of the heterocycle 1 from the xylylene-bis-phosphonium salt 2 and PCI3 proceeds via a detectable intermediate 3 in a cascade of condensation reactions that is terminated by spontaneous heterolysis of the last remaining P-Cl bond in a cyclic bis-ylide-substituted chlorophosphine formed (Scheme 1) [15]. The reaction scheme is applicable to an arsenic analogue of 1 [15] and to bis-phosphonio-benzophospholides with different triaryl-, aryl-alkyl- and aryl-vinyl-phosphonio groups [16, 18, 19], but failed for trialkylphosphonio-substituted cations here, insufficient acidity prohibited obviously quantitative deprotonation of the phosphonium salts, and only mixtures of products with unreacted starting materials were obtained [19]. The cations were isolated as chloride or bromide salts, but conversion of the anions by complexation with Lewis-acids or metathesis was easily feasible [16, 18, 19] and even salts with organometallic anions ([Co(CO)4] , [CpM(CO)3] (M=Mo, W) were accessible [20]. 

With the usual reaction of organometallic reagents with acid derivatives (ester or acid chloride), the starting materials can add two equivalents of organometallic compound. The ketone generated after the first addition is quite reactive, and there is quite no selectivity between it and the starting acid derivative ... 

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