Allene chemistry

• Kay M. Brummond

Beilstein J. Org. Chem. 2011, 7, 394–395, doi:10.3762/bjoc.7.50

• ...” [1]. I first became interested in allenes as a graduate student with Professor Ray Funk at Pennsylvania State University while working on the preparation of ene–diyne systems. Interestingly, I always seemed to isolate allenes instead of the compounds I was hoping to obtain. My interests in allenes

Recent advances in the development of alkyne metathesis catalysts

• Xian Wu and
• Matthias Tamm

Beilstein J. Org. Chem. 2011, 7, 82–93, doi:10.3762/bjoc.7.12

• metathesis polymerization (ROAMP) and acyclic diyne metathesis polymerization (ADIMET) are known (Scheme 2). In contrast to olefin metathesis, the number of catalysts for alkyne metathesis is far more limited. The first catalyst for alkyne metathesis was a heterogeneous system based on WO3/silica, which was

• = NMe2) was hardly successful in the presence of 2 mol % of the catalyst, whereas 14e was isolated in 90% yield with a catalyst loading of 5 mol %. Further detailed studies are required to fully explain this ostensibly odd behavior. Catalyst 5 was used in the RCAM of 6,15-dioxaeicosa-2,18-diyne (15) and

(−)-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