Highly Stereoselective Total Syntheses of β-Farnesene, β-Sinensal, and Dendrolasin Employing 2-(Hydroxymethyl)-4-(phenylthio)-1-butene as a Building Block

Article abstract of DOI:10.1021/jo00174a007

The use of 2-(hydroxymethyl)-4-(phenylthio)-1-butene (2) for the synthesis of the title compounds is described.The aldehyde 4 obtained by Claisen rearrangement of 2 via vinyl ether was converted to 5a by 2-propenyllithium.The carboxylic acid 6a was provided by the Claisen rearrangement of 5b via siloxy vinyl ether.The aldehyde 6d was obtained by reduction of 6a with LiAlH4 followed by oxidation of 6c with NCS-Me2S-Et3N.Treatment of 6d with Ph3P=CH2 gave 7a, which was transformed to β-farnesene (1a) by oxidation followed by pyrolysis.Then, treatment of 6d with CH3CH (Li)CH=NC6H11 gave 7c, which was converted to β-sinensal (1b).The sulfoxide 7b was treated with Ac2O-catalytic (CF3CO2)O at room temperature for 72 h to give 8a, which was transformed to 8b by reduction with NaBH4.Epoxidation of 8b followed by oxidation gave dendrolasin (1c).