Diethoxyaluminum hydride, lithium

Other methods for the preparation of cyclohexanecarboxaldehyde include the catalytic hydrogenation of 3-cyclohexene-1-carboxaldehyde, available from the Diels-Alder reaction of butadiene and acrolein, the reduction of cyclohexanecarbonyl chloride by lithium tri-tcrt-butoxy-aluminum hydride,the reduction of iV,A -dimethylcyclohexane-carboxamide with lithium diethoxyaluminum hydride, and the oxidation of the methane-sulfonate of cyclohexylmethanol with dimethyl sulfoxide. The hydrolysis, with simultaneous decarboxylation and rearrangement, of glycidic esters derived from cyclohexanone gives cyclohexanecarboxaldehyde. 

The cyclohexene 121, which was readily accessible from the Diels-Alder reaction of methyl hexa-3,5-dienoate and 3,4-methylenedioxy-(3-nitrostyrene (108), served as the starting point for another formal total synthesis of ( )-lycorine (1) (Scheme 11) (113). In the event dissolving metal reduction of 121 with zinc followed by reduction of the intermediate cyclic hydroxamic acid with lithium diethoxyaluminum hydride provided the secondary amine 122. Transformation of 122 to the tetracyclic lactam 123 was achieved by sequential treatment with ethyl chloroformate and Bischler-Napieralski cyclization of the resulting carbamate with phosphorus oxychloride. Since attempts to effect cleanly the direct allylic oxidation of 123 to provide an intermediate suitable for subsequent elaboration to ( )-lycorine (1) were unsuccessful, a stepwise protocol was devised. Namely, addition of phenylselenyl bromide to 123 in acetic acid followed by hydrolysis of the intermediate acetates gave a mixture of two hydroxy se-lenides. Oxidative elimination of phenylselenous acid from the minor product afforded the allylic alcohol 124, whereas the major hydroxy selenide was resistant to oxidation and elimination. When 124 was treated with a small amount of acetic anhydride and sulfuric acid in acetic acid, the main product was the rearranged acetate 67, which had been previously converted to ( )-lycorine (108). 

Rosenmund reaction Tetramethylthiourea. Lithium diethoxyaluminum hydride. Wolff-Kishner, Huanc-Minlon reduction Hydrazine. Potassium r-butoxide-Dimethyl sulfoxide. Triethanolamine. 

Various cyclopropanecarbonitriles have been converted to the corresponding cyclopro-panecarbaldehydes using diisopropylaluminum hydride, " - tri-hexylsilane, " lithium aluminum hydride, lithium diethoxyaluminum hydride, and lithium bis(2-methoxyethoxy)aluminum hydride as reducing agents. The yields were at best moderate. 

Lithium dicyclohexylamide [1, 610, before Lithium diethoxyaluminum hydride]. 

Lithium diethoxyaluminum hydride [LiAlH2(OEt)2] and the monoethoxy derivative [LiAlH3(OEt)] have been used in syntheses. It is clear, however, that LiAlH(Ot-Bu)3 is one of the more commonly used reagents. It is stable in solution, gives useful concentrations in ether solvents (36 g/100 g of solvent in THE,... 

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