Chloromethyl Methyl Ether → 5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-1-bromo-2-methoxymethoxynaphthalene-3-carboxylic acid

Participants

Reaction Steps

5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2-hydroxynaphthalene (Compound H, available in accordance with the publication Krause Synthesis 1972 140), is the starting material in the example shown in Reaction Scheme 2. Compound H is brominated to provide the corresponding 3-bromo compound (Compound I) which is thereafter protected in the hydroxyl function by treatment with methoxymethyl chloride (MOMCl) to yield 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-3-methoxymethoxy-2-bromonaphthalene (Compound J). Compound J is reacted with t-butyllithium and carbon dioxide to provide the corresponding carboxylic acid (Compound K) from which the methoxymethyl protecting group is removed by acid to give 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-hydroxynaphthalene-3-carboxylic acid (Compound L). Compound L is brominated to yield 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-1-bromo-2-hydroxynaphthalene-3-carboxylic acid (Compound M). Compound L and Compound M serve as reagents in accordance with Formula 6. The hydroxy group of Compound X is protected for further transformations with methoxymethyl chloride (MOMCl) in the presence of base, yielding 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-1-bromo-2-methoxymethoxynaphthalene-3-carboxylic acid (Compound N). ##STR5##

Provenance & Evidence