Method for producing N,N-dialkylhomofarnesic acid amide

A method for producing (±)-3a,6,6,9a-tetramethyldodecahydronaphtho[2.1-b]furan, comprising Steps 1-4 below:

• Step 1:
• reacting nerolidol with N,N-dialkylformamide dimethyl acetal under the conditions that the N,N-dialkylformamide dimethyl acetal can be refluxed to produce N,N-dialkylhomofarnesic acid amide, wherein the molar ratio of the N,N-dialkylformamide dimethyl acetal to the nerolidol is in a range of 1.5 to 3;
• Step 2:
• cyclizing the N,N-dialkylhomofarnesic acid amide obtained in Step 1 in the presence of an acidic agent and further hydrolyzing to obtain Sclareolide;
• Step 3:
• reducing the Sclareolide obtained in Step 2 so as to obtain Ambroxdiol;
• and
• Step 4:
• dehydrating and cyclizing the Ambroxdiol obtained in Step 3 so as to obtain (±)-3a,6,6,9a-tetramethyldodecahydronaphtho[2.1-b]furan.