Allylmagnesium chloride

The combination of metal tuning and double stereodifferentiation helps to prepare chelation and nonchelation products in the imine series7. In the case of an alkoxy substituent adjacent to the aldimino, the chelation product 10 is predominantly obtained with allylmagnesium chloride, chloromagnesium allyltriethylaluminate or allylzinc bromide, while the use of allyl-boronates or allyltitanium triisopropoxide, which lack the requisite Lewis acidity for chelation, gives 11 with good Cram selectivity. 

The results show that modest chelation control can be obtained using organomctallics like allylmagnesium chloride, chloromagnesium allyltriethylaluminate and allylzinc bromide, which are capable of /1-chelation. In contrast to this, 9-allyl-9-borabicyclo[3.3.1]nonane (9-allyl-BBN)... 

Mg. Li and co-worker first reported magnesium-mediated Barbier-Grignard allylation of benzaldehyde in water (Eq. 8.73).172 Recently, a study was completed in which some water-tolerant allylating agents were prepared in situ from allylmagnesium chloride and various metallic salts reacted with aldehydes in THF-FLO to afford the desired homoallylic alcohols.173... 

Glyoxal-sodium bisulfite, 30, 86 Glyoxylic acid, w-butyl ester, 35, 18 ethyl ester, diethyl acetal, 35, 59 Grignard reaction, addition to ethyl sec-butylidenecyanoacetate, 35, 7 allylmagnesium bromide with of,(3-di-bromoethyl ethyl ether, 36, 61 allylmagnesium chloride with a,/3-di-bromoethyl ethyl ether, 36, 63 ethylmagnesium bromide with tin tetrachloride, 36, 86... 

Reactions of Allylation and Propargylation Allylation of prochiral and chiral nitrones (292) with allylmagnesium chloride leads to homoallylic hydroxylamines (416), which via an iodo cyclization step are converted to 5-(iodomethyl)isoxazolidines (417) (Scheme 2.186) (202, 213, 666-668). 

The preparation of vicinal diallyldiamines is illustrated by the following sequence condensation of glyoxal with benzhydrylamine yields the diimine 189, which is converted into 190 by the action of allylmagnesium chloride. The diphenylmethyl groups are then removed reductively by treatment with triethylsilane196. 

Treatment of aromatic nitro compounds with allylmagnesium chloride, followed by 1.4 equiv. of LiAlH LAH) and a trace of palladium on charcoal affords hydroxylamines 387 (Ar = Ph, 4-CIC6H4, 2-FC6H4 or 3-MeOC6H4). If the amount of LAH is increased to 2.5 equiv. iV-allylarylamines 388 result. 1-Nitrohexane and nitrocyclohexane react analogously426. 

Diacid 54 was prepared by coupling a-a -di-bromo-m-xylene with allylmagnesium chloride, followed by Ru04-mediated cleavage of the resultant diene [29]. Diacid 54, prepared by an alternative route, was already a known compound Ruggli, P. Bucheler, P. Heb. Chim. Acta 1947, 30, 2048. 

Another method for the alkylidenation of aldonolactones uses addition of organ-ometallic reagents [78]. For example, Lin et al. [85] described an efficient route to conjugated anomeric dienes or aldehydes based on the reaction of aldono-1,4- and aldono-1,5-lactones (1, 62) with allylmagnesium chloride (Scheme 19), giving allyl hemiacetals (e.g., 63a, b). Hemiacetal can be dehydrated [e.g., with (CF3C0)20] to produce dienes 64a, b, or ozonolyzed (e.g., to give 65). 

Scheme 19 C-Glycosyl derivatives by addition of allylmagnesium chloride to aldonolactones...

Jurczak and Kiegiel reported that additions of allylmagnesium chloride and allyl bromide in the presence of Zn to iV-methyl and W-phenylglyoxyloyl-(2R)-borane-10,2-sultam occurred in a diastereoselective manner. Similarly, the Lewis acid mediated addition of allyltrimethylsilane also gave good diastereoselectivity and in the case with TiCU a change of direction of asymmetric induction was observed <99TL1009>. 

The reaction of allylmagnesium chloride with methylaluminium dichloride affords, after workup of the reaction mixture and recrystalUzation from THF, a rather unexpected compound (7), which, according to its crystal-strucmre determination, appears to consist of [(allyl)2Mg3Cl3(THF)6]+ cations and [(allyl)4Mg] anions in a 2 1 molar ratio (Figure 8). ... 

Tetsuaki Tanaka of Osaka University has reported (Tetrahedron Lett. 45 75, 2004) what appears to be a general route to alkylated quaternary centers, based on the Ti-mediated addition of allylmagnesium chloride to the Sharpless-derived epoxy ether 4. Remarkably, the conversion of 6 to 7 works equally well. 

We have put forward (J. Am. Client. Soc. 2004, /26, 13900) an alternative approach to the enantioselective construction of cyclic quaternary centers. Addition of phenylacetylene to cyclopentanone followed by dehydration and Shi epoxidation gave the epoxide 10. Opening of the epoxide with allylmagnesium chloride proceeded with inversion, to give II. The alcohol 11 can also be carried on to bicyclic products, exemplified by the sulfone 12. 

A new synthesis of propenyl ketones involves reaction of an ester with 2 equiv. of allylmagnesium chloride (or methallylmagnesium chloride) to form the tertiary... 

A recent variant of the three-component coupling reaction employs an allylzirco-nium reagent, obtained from zirconocene dichloride and allylmagnesium chloride (Scheme 6.18) [32],... 

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