Organometallic compounds acylation

Similarly, 1-alkylpyrroles, indoles, furans, thiophenes [60], a-picoline [61], enols, malonates [76], and organometallic compounds [56, 62] react with acyl imines of trifluoropyruvates to give derivatives of a-trifluoromethyl a-amino acids... 

Phthalic anhydride also shows the ability to inhibit thermal destruction of polyolefins [21]. Among the organometallic compounds may be quoted organotin compounds R2Sr(OR )2, where R2 means alkyl, aryl, or cycloalkyl OR means alkoxyl, acyl, or R2Sn(CH2COORi)2, where Rj—Ci—Cm means alkyl, allyl, or benzyl Ro represents chloro-, mono-, or triorga-notin mercaptans [22,23]. 

The Conversion of Acyl Halides to Ketones With Organometallic Compounds ... 

Reaction between acyl halides and organometallic compounds 10-115 Reaction between other acid derivatives and organometallic compounds... 

Halogenation of alkenyl organometallic compounds Addition of hydrogen halides to triple bonds Halogenation of alkynes or allenes Addition of alkyl halides to triple bonds Addition of acyl halides to triple bonds... 

Yu. A. Ol dekop and N. A. Maier, Synthesis of Organometallic Compounds by Decarboxylation of Metal Acylates. Science and Technology, Minsk, 1976. 

II c., Cl 0 M L- X c Reaction of acyl halides or other acid derivatives with organometallic compounds... 

Acylation is one of the most fundamental and useful reactions in organic synthesis and is normally achieved by the reaction either with carboxylic acid derivatives and organometallic compounds or with masked acyl anions and aUcyl halides. 

Markl, Lieb and Merz have described the carbanionic addition of lithium or magnesium organometallic compounds to the P atom of 2.4.6-triphenyl-X -phos-phorins, which form deep red s ts 143. These can be alkylated either at the P atom to form X -phosphorins 144 or at C—2 to yield 1,2-dihydro-X -phosphorins 145. Acylation with benzoylchloride affords the 1,4-dihydro-X -phosphorin derivatives 146. Addition of acids or water leads to the synthetically important intermediates 147 which can be reconverted to the X -phosphorin-salts 143 by 2 N NaOH. 

The Conversion of Organometallic Compounds to Ketones, Aldehydes, Carboxylic Esters, or Amides Acyl-de-metallation, etc. 

Reaction of halo ketones or diazo ketones with boranes 0-102 Carbonylation of alkyl halides 0-104 Reaction between acyl halides and organometallic compounds 0-105 Reaction between other acid derivatives and organometallic compounds... 

Isomerization of a-hydroxy alkynes and alkynones 2-15 Acylation of olefins 2-27 From lithium acetylides 2-32 From vinylic organometallic compounds... 

The reaction of CO with some of the preceding organometallic compounds is rapid at room temperature and pressure and insertion of CO into the Ni—C bond results (equation 175).1445 In the case of the np3 ligand the first product isolated is a solid solution of the acyl derivative of nickel(II), [Ni(COR)(np3)]+, and a carbonyl complex of nickel(I), [Ni(CO)(np3)]+, in a 1 1 ratio. When this solid solution is dissolved in THF and EtOH, the pure acyl derivative (190) resulted. The acetyl derivative spontaneously loses CO on exposure to air restoring the original methyl derivative. 

A similar lipase/ruthenium combination of an enzyme with an organometallic compound was employed to resolve racemates of allylic alcohols to allylic acetates of high optical purity and more than 80% yield in the presence of an acyl donor (Lee, 2000). 

Most SN reactions of hydride donors, organometallic compounds, and heteroatom-stabi-lized carbanions at the carboxyl carbon follow the mechanism shown in Figure 6.2. Thus, the substitution products, i.e., the aldehydes and ketones C, form in the presence of the nucleophiles. Thus, when the nucleophile and the acylating agent are used in a 2 1 ratio, alcohols F are always produced. 

Fig. 6.40. On the chemo-selectivity of the reactions of hydride donors, organometallic compounds, and heteroatom-stabilized "carbanions with acylating agents (kM t refers to the rate constant of the addition of the nucleophile to the carboxyl carbon, and kadd2 refers to the rate constant of the addition of the nucleophile to the carbonyl carbon).

For the reaction of hydride donors, organometallic compounds and heteroatom-stabilized carbanions with acylating agents or carbonyl compounds one encounters a universal reactivity order RC(=0)C1 > RC(=0)H > R2C=0 > RC(=0)0R > RC C NR It applies to both good and poor nucleophiles, but—in agreement with the reactivity/selectivity principle (Section 1.7.4)—the reactivity differences are far larger for poor nucleophiles. 

To make as much carboxylic acid derivative as possible available to the nucleophile at all stages of the reaction, the nucleophile is added dropwise to the carboxylic acid derivative and not the other way around. In Figure 6.41, the approach to chemoselective acylations of hydride donors and organometallic compounds, which we have just described, is labeled as strategy 2 and compared to two other strategies, which we will discuss in a moment. 

Acylation of Organometallic Compounds and Heteroatom-Stabilized Carbanions With Carboxylic Acid (Derivative)s Synthesis of Ketones... 

Fig. 6.44. Chemoselective acylation of an organometallic compound C with the Weinreb amide D of Figure 6.21 a general approach to ketones.

Fig. 6.47. Top three reactions chemoselective acylations of weakly nucleophilic organometallic compounds with carboxylic acid chlorides.

---