Methyl aluminum bis

Butylmagnesium bromide-Methyl-aluminum bis(2,6-di-/-butyl-4-methyl-phenoxide), 203... 

Diisobutyl(iodomethyl)aluminum, 114 Dimethylaluminum chloride, 5 Ethylaluminum dichloride, 5, 44, 306 Ethylmagnesium bromide-Methyl-aluminum bis(2,4,6-tri-r-butyl-phenoxide), 203 Isobutyl(2,4,6-tributylphenoxy)-aluminum trifluoromethanesulfonate, 113... 

The choice of Lewis acid promoter for these reactions can change the sense of asymmetric induction. " For example, tandem [4 + 2]/ [3 + 2] cycloadditions (eq 4) mediated by Ti(0-i-Pr)2Cl2, followed by hydrogenolysis afforded tricyclic (-)-a-hydroxy lactam [(-)-8] in 98% ee. When mediated by methyl-aluminum-bis(2,6-diphenylphenoxide) (MAPh), the same reaction gave (+ )-8 in 93% ee. Importantly, the observed selectivity is not chiral auxiliary dependent. Rather, it is attributed to a highly endo selective cycloaddition in the case of Ti compared to high exo selectivity in the case of MAPh. 

The first example of this type of living-radical polymerization was reported by Sawamoto, who used a ruthenium metal complex in association with methyl-aluminum bis(2,6-di- ert-butylphenoxide), as an accelerator, to polymerize methyl... 

MABR = methyl aluminum bis-(4-lHDmo-2,6-di-/-butylphenoxide) Maruoka, K. Bureau, R. Ooi, T. Yamamoto. H. SmLetu 1991,491. 

MABR=methyl aluminum bis(4-l>romo-2,6-dir4iutylphenoxide) Maruoka, K. Ctmcepcion, A.B. Yamamoto. H. SynLett, 1992, 31. 

SnCLu Ti(OPr )2Cl2, and methyl acetylenedicarboxylate (MAD) (bis(2,6-/< r/-butyl-4-methylphenoxy)-methyl-aluminum) are most often used as LA. Meanwhile, nonconventional procedures, for example, the reaction in water (102 and references therein), can be used to perform cycloadditions of nitroalkenes. 

Methylaluminum bis(4-bromo-2,6-di-tert-butyiphenoxide) Aluminum, bis[4-bromo-2,6-bis(1,1-dimethylethyl)phenolato]methyl- (12) (118495-99-1)... 

We note that while tin reagents have often been employed for the organoboron halides/ the use of organostannanes as starting materials can also be applied to the synthesis of heavier group 13 derivatives. In the context of polyfunc-tional Lewis acid chemistry, this type of reaction has been employed for the preparation of ort/ o-phenylene aluminum derivatives. Thus, the reaction of 1,2-bis(trimethylstannyl)benzene 7 with dimethylaluminum chloride, methylaluminum dichloride or aluminum trichloride affords l,2-bis(dimethylaluminum)phenylene 37, l,2-bis(chloro(methyl)aluminum)phenylene 38 and 1,2-bis(dichloroalumi-num)phenylene 39, respectively (Scheme 16). Unfortunately, these compounds could not be crystallized and their identities have been inferred from NMR data only. In the case of 39, the aluminum derivative could not be separated from trimethyltin chloride with which it reportedly forms a polymeric ion pair consisting of trimethylstannyl cations and bis(trichloroaluminate) anions 40. 

Bis(2,4-pentanedionato)copper(II) obtained from a commercial source should be dried under vacuum before use. The methyl aluminum reagent AlMe2(0 Pr) can be prepared by slow addition of /-PrOH to a hexane solution of AlMe at-TS °C and purified by vacuum distillation (bp 34-36 °C/0.05 mmHg). 

These arrangements are presumably controlled in part by the intramolecular nature of the proton transfer stage of the reaction. While the same stereochemistry is obtained with a variety of Lewis acids, e.g., dimethylaluminum chloride, boron trifluoride-diethyl ether complex, tin(IV) chloride, the opposite preference is observed with bis[4-bromo-2,6-di-/m-buty]phen-oxy](methyl)aluminum (MABR)104 (see Table 6, entries 4-7 and the following example). 

Rearrangement of l-methyl-2-propenyl vinyl ether with bis(2,6-diphenylphenoxy)methyl-aluminum at — 20 °C results in the almost exclusive formation of the (E)-isomer [85% d.r. (E/Z) 97 3],... 

REDUCTIVE METHYLATION Sodium bis-(2-methoxyethoxy)aluminum hydride. 

SiMe3)2CH]2Al-Al[CH(SiMe3)2]2. This compound was prepared by the potassium reduction of bis[bis(trimethylsilyl) methyl]aluminum chloride (equation 1). ... 

MABR = bis(4-hromo-2,6-di-tert butylphenoxy) methyl aluminum... 

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