1- Tetralones Birch reduction

The preparation of 6-methoxy-2-naphthol is of particular interest as the starting point in many synthetic sequences. It is readily converted to 6-methoxy-2-tetralone through a Birch reduction... 

The association of the xanthate-based tetralone synthesis with the alkyla-tive Birch reduction and other reactions allowing the modification of the aromatic core constitutes a particularly potent combination. This is illustrated by the expedient synthesis of tricyclic system 65 pictured in the top part of Scheme 36 (Cordero-Vargas et al, personal communication). Routes to highly complex architectures can be conceived through modification of the olefinic partner, the substitution pattern of the aromatic moiety, or the nature of the alkylating agent associated with the Birch reduction. 

Reductive alkylation of a-tetralones, a-Tetralone (1) has been converted into 2 in 607 yield by Birch reduction with potassium and r-butyl alcohol in liquid ammonia at —78° followed by addition of lithium bromide and then methyl iodide. Australian chemists have found that this reductive alkylation is gener-... 

Synthesis of racemic (178) is shown in Scheme 37. Ketoester (177), synthesized from naphthalene-1,6-diol via 5-methoxy-2-tetralone, was converted into compound (180) by successive methylation at C-4, acetali-zation at C-3, reduction of the ester group to hydroxymethyl group, epoxidation of the C-5, C-6 double bond, and ring opening of the epoxide. Birch reduction of diol (180) with 18 equivalents of lithium in liquid ammonia followed by acid hydrolysis and subsequent methyl acetalization... 

The procedure that proved successful proceeded from the tricyclic compound XV, prepared from 6-methoxyl-l-methyl-2-tetralone, which was obtained from Schaeffer s salt by well-known procedures. The intermediate XVI was transformed into XVII by a Birch reduction follow ed by acetylation and mild acid hydrolysis. The, y-unsaturated... 

Stork and coworkers [127] were the first to demonstrate that hthium enolates are formed in the course of a Birch reduction of enones with lithium in ammonia, that they are regio-stable and can be trapped by electrophiles, as shown by the formation of traws-tetralone 111 through enolate 110 (Scheme 2.33). 

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