First total synthesis of acetylenic alcohol 15-methyltricosa-2,4-diyne-1, 6-diol (strongylodiol-G) derived from marine sponge

<div><p>The first total and efficient synthesis of a naturally occurring acetylenic alcohol 15-methyltricosa-2,4-diyne-1,6-diol (strongylodiol-G) derived from marine sponge involving nine steps has been described. 1-Bromo-9-methyloctadecane (<b>5</b>) and hex-6-tetrahydropyranyloxyhex-2,4-diyn-1-al (<b>9</b>) which were initially synthesised separately starting from 1,8-octanediol (<b>1</b>) and propargyl alcohol (<b>6</b>), respectively, have been used as the final intermediates to obtain the title compound. The key steps in the synthesis involved ionic liquid-mediated bromination of 1,8-octanediol (<b>1</b>), tetrahydropyranylation of 8-bromooctan-1-ol (<b>2</b>) using acidic ionic liquid [bmim]HSO<sub>4</sub> and monotetrahydropyranylation of hex-2,4-yn-1,6-diol (<b>7</b>) using ultrasonic energy.</p></div>