Grignard coupling reactions

Another area of interest to the industrial sector is the development of a more efficient synthesis of biaryl compounds. This has been accompHshed using a Ni(II)-cataly2ed Grignard coupling reaction with an aryl haUde (86—89). 

Banning,43 who synthesized 1,4-naphthalene oligomer using a Grignard coupling reaction with 1,4-dibromonaphthalene as the starting material. The IR spectra of PNT-N prepared in this work all have this absorption at 699 cm-1. Films collected from different VDP reactions always exhibit this specific absorption, between 696-699 cm-1. 

M. Malanga and O. Vogl, Head-to-head polymers. XXIV. Synthesis of head-to-head polyisobutylene by grignard coupling reaction, ]. Polym. Sci., Part A Polym. Chem., 21(9) 2629-2648,1983. 

SCHEME 76. Mechanism of Ni-catalyzed Grignard coupling reaction. 

A regio- and stereocontrolled copper catalyzed allylic alkylation has been recently reported [219]. With the thiophenolate copper catalyst 150, the Grignard-coupling reaction provided only the y-allylated product in quantitative yield, albeit with modest enantioselectivity (Eq. 8E.33). 

To improve the preparative method of phospha sugars from sugar starting materials [21,22], the Arbzov reaction and Grignard coupling reaction have been applied to a reaction of 1,4-dibromobutane. The reaction of 1,4-dibromobutane (53) with dimethyl phenylphosphonite to give ethyl (4-bromobutyl)phenylphosphinate (54) and successive intramolecular substitution of the 4-bromo substituent with phosphinyl anion affords 1-phenyl -phospholane 1-oxide (56a) in 40% yield. It can also be prepared from... 

The 2- and 3-phospholenes are prepared by the McCormack reaction and are good candidates as starting materials for the preparation of five-and six-membered phosphorus heterocycles [25-27]. From l-methoxy-3-methyl-2-phospholene 64 or l-methoxy-2,3-diacetoxy-3-methylphospholane 67, l-aryoxy-3-methyl-2-phospholenes 66a-c (Scheme 19), or l-aryoxy-2,3-diacetoxy-3-methylphospholane 69 (Scheme 20) with a substituted phenyl group at phosphorus, or l-aryl-3-methyl-2-phospholenes 71a-g (Scheme 21) are prepared by a substitution reaction and/or a Grignard coupling reaction [28,29]. 

The other primary application of asymmetric Grignard coupling reactions has been in the synthesis of axially chiral binaphthyl and biphenyl derivatives. Hayashi performed a binaphthyl synthesis (equation 6) in 95% ee using a nickel catalyst and ligand (7), a P-O chelating analog to (3). For a similar synthesis of chiral biaryls (equation 7) ligand, (8) was found to yield the most successful results (93% ee). ... 

In 1971, Kochi reported that a catalytic silver salt induced Grignard coupling reaction with organic halides to form hydrocarbons [428,429 Eqs. (185), (186) and (187) 22,428]. However, the pair- [see Eq. (185)] and the stereoselectivity [see Eq. (187)] were not satisfactory hence, similar reactions with copper, nickel, or palladium catalysts are far more common. If a coupling reaction to be carried out involves RMgX and RX having the same R group, a silver catalyst still finds a use [Eq. (188) 430]. 

Spectacular enantioselection has been observed in hydrogenation (cf. Section 2.2) [3] and hydrometallation of unsaturated compounds (cf. Section 2.6) [4], olefin epoxidation (cf Section 2.4.3) [5] and dihydroxylation (cf Section 3.3.2) [6], hydrovinylation (cf Section 3.3.3) [7], hydroformylation (cf Section 2.1.1) [4a, 8], carbene reactions [9] (cf Section 3.1.10), olefin isomerization (cf Section 3.2.14) [10], olefin oligomerization (cf Section 2.3.1.1) [11], organometallic addition to aldehydes [12], allylic alkylation [13], Grignard coupling reactions [14], aldol-type reactions [15], Diels-Alder reactions [12a, 16], and ene reactions [17], among others. This chapter presents several selected examples of practical significance. 

Transition Metal Catalyzed Grignard Coupling Reactions. 66... 

A Concise Account of Recent Sn2 Grignard Coupling Reactions in Organic Synthesis ... 

When one considers how synthetic chemistry has impacted the development of conjugated polymers, there is no better example than the poly(3-alkylthio-phenes) (P3ATs, 4). Early work focused on oxidative polymerization methods as a means of preparing soluble forms of this polymer. Subsequently, Grignard coupling reactions were able to prepare the polymer directly in the... 

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