(−)-Complanine, an inflammatory substance of marine fireworm: a synthetic study

• Kazuhiko Nakamura,
• Yu Tachikawa and
• Daisuke Uemura

Beilstein J. Org. Chem. 2009, 5, No. 12, doi:10.3762/bjoc.5.12

• acetylene 4 in 51% yield [7]. The bromomagnesium salt of 4 generated with EtMgBr was successively treated with 1-iodopent-2-yne in the presence of CuI to give the corresponding diyne compound 5 in 43% yield [8]. The partial reduction was achieved by using Lindlar catalyst to give the desired Z olefin, which

• ), 1.69 (1H, m), 1.57 (4H, m), 0.84 (3H + 3H, t, J = 7.6 Hz, overlapped). Synthesis of diyne 5: To a solution of the alkyne (4, 445 mg, 2.45 mmol) in THF (2.0 ml), 1.6 M solution of ethylmagnesium bromide (Aldrich, 2.45 ml, 3.92 mmol) was added under N2, and the resulting solution was stirred at ambient

• extractive workup and column chromatography (SiO2, hexane/ethyl acetate 98 : 2 to 95 : 5) gave the desired diyne compound 5 as a pale yellow oil (258 mg, 43%). 5: [α]D26 +2.7 (c 0.26, CHCl3); HRMS (ESI) calcd for C16H24O2Na [(M + Na)+] 271.1674, found 271.1696; 1H NMR (600 MHz, CDCl3) δ 4.17 (1H, m), 4.09