Ethyl magnesium halides

The epimeric 17 -methylandrost-5-ene-3, 17a-diol could be isolated as a by-product from larger scale experiments. Reaction of (49) with ethyl-magnesium halide affords the corresponding 17a-ethyl compound. In this... 

Table 11.4. 1,2-Disubstituted cyclopropanols 22 from carboxylic acid esters 8 and 2-substituted ethyl-magnesium halides in the presence of titanium tetraisopropoxide or chlorotitanium triisopropoxide. Entry Starting Product Conditions Yield Ref. Ester R1 R3 [mol% (%) R2 Ti(OR)4] (d. r. Z/Eb) ...

The required Grignard reagents are formed from the substituted guanidines and ethyl magnesium halide in ether [59), with simultaneous evolution of ethane. Their assigned structure (XLV) accounts satisfactorily for their reactions, although their true structure will obviously be essentially ionic and exhibit resonance effects. 

The zirconium-catalyzed carbometalation reaction has been developed from the initial observation by Dzhemilev in 1983 that Cp2ZrCl2 (1) catalyzes the addition of ethyl-magnesium halide to unactivated alkenes [104-106]. A plausible mechanism for this carbometalation involves zirconocene and zirconacyclopentane species (Scheme 6.5) [107-109]. Diastereo- and enantioselective carbomagnesation is accomplished by use of chiral fl .sa-zirconocene derivative [110]. 

Table 11.4. 1,2-Disubstituted cyclopropanols 22 from carboxylic acid esters 8 and 2-substituted ethyl-magnesium halides in the presence of titanium tetraisopropoxide or chlorotitanium triisopropoxide.

Propanal is treated with ethyl magnesium halide (with diethyl ether H30 ). Which of the following is true regarding this reaction ... 

Nitrogen fixation under milder conditions using a transition metal catalyst has been reported. The reaction is a simple one Nitrogen was bubbled into a mixture of transition metal halides and ethyl magnesium halide in ether. A typical reaction is shown in Fig. 6-12. 

Selenophene chloromethyl derivatives readily form di(/3-hydroxy-ethyl)aminomethylselenophenes (8) which, with thionyl chloride, give the corresponding di(/3-chloroethyl)aminomethylselenophenes (9).103 Chloromethylselenophenes condense with trisubstituted ethylene-diamines to yield tetrasubstituted diamines containing the selenophene nucleus.104 The reaction of 2-chloromethylselenophene with sodium derivatives of malonic and acetoacetic ester yields the acid (10) and ketone (11), respectively, whereas with alkyl magnesium halides 2-(alkylmethyl)selenophenes are formed.105... 

To the product from Step 1, 1,10-phenanthroline monohydrate (2.97 mmol) dissolved in 1.5 L THE containing N,N-tetramethylenediamine (893 mmol) was added ethyl magnesium bromide (348.1 mmol) in THE along with trimethylchlorosilane (325.9 mmol) until a phenanthroline color change occured. The mixture was cooled to — 27 °C until the halide... 

Codeine is unaffected by Grignard reagents [374], but codeine methyl ether forms simple addition complexes with ethyl- and phenyl-magnesium halides these are readily decomposed with liberation of the unchanged base [375]. 

From the alkoxymagnesium halide derived from a tertiary alcohol (prepared from the alcohol with ethyl-magnesium bromide) with phthalic anhydride in ether or an ether-dioxan mixture. 

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