General method for iron-catalyzed multicomponent radical cascades–cross-couplings
作者:Lei Liu、Maria Camila Aguilera、Wes Lee、Cassandra R. Youshaw、Michael L. Neidig、Osvaldo Gutierrez
DOI:10.1126/science.abj6005
日期:2021.10.22
addition to vinyl boronates) with Grignard reagents. Then, we extended the scope of these radical cascades by developing a general and broadly applicable Fe-catalyzed multicomponent annulation–cross-coupling protocol that engages a wide range of π-systems and permits the practical synthesis of cyclic fluorous compounds. Mechanistic studies are consistent with a bisarylated Fe(II) species being responsible
过渡金属催化的交叉偶联反应是化学合成中应用最广泛的一些方法。然而,尽管铁 (Fe) 作为一种潜在的更便宜、更丰富、毒性更小的过渡金属催化剂具有显着优势,但其在多组分交叉偶联中的实际应用仍然很大程度上不成功。我们展示了 1,2-双(二环己基膦基)乙烷 Fe 催化的 α-硼基自由基(由选择性自由基加成到乙烯基硼酸盐产生)与格氏试剂的偶联。然后,我们通过开发一种通用且广泛适用的 Fe 催化多组分环化-交叉偶联方案扩展了这些自由基级联的范围,该方案涉及广泛的 π 系统并允许实际合成环状氟化合物。
Carbon monoxide as a building block in organic synthesis. Part V. Involvement of palladium-hydride species in carbonylation reactions of monoterpenes. X-ray crystal structure of [Ph3PCH2CHCHPh]4[PdCl6][SnCl6]
A palladium precursor and SnCl2 as cocatalyst were used under 4 MPa of carbonmonoxide for the catalytic alkoxycarbonylation of several monoterpenes into C11 esters. The active catalyst involves a palladium-hydride species whose formation was investigated. In the case of the model substrate 3-phenylpropene, the source of the hydrido ligand was determined to be the alkene itself. Allylic hydrogen abstraction
Pyrolysis of the acetate of (+) (1R:4R:6S)-Carane-trans-4-ol (I) 10 Torr and temperatures between 386 and 604° yields acetic acid and a mixture of the hydrocarbons (+) (1R:6S)-Δ4-Carene (III), (+) (1R:6S)-Δ3-Carene (IV), and (+) (1R:4R)-trans-Δ2,8-p-menthadiene (VI), the composition of which depends on the temperature. The same hydrocarbons are formed by pyrolysis of (+) (1R:4S:6S)-carane-cis-4-ol (II)
(+)(1R:4R:6S)-Carane - trans -4-ol(I)的乙酸盐的热解,温度介于386和604°之间,产生乙酸和碳氢化合物(+)的混合物(1R: 6S)-Δ 4 -Carene(III),(+)(1R:6S)-Δ 3 -Carene(IV),和(+)(1R:4R) -反式-Δ 2,8 - p -menthadiene(VI ),其成分取决于温度。通过(+)(1R:4S:6S)-顺式--4-醇(II)的热解形成相同的烃。
Liquid-phase noncatalytic oxidation of monoterpenoids with nitrous oxide
作者:E. P. Romanenko、E. V. Starokon’、G. I. Panov、A. V. Tkacheva
DOI:10.1007/s11172-007-0187-9
日期:2007.6
A series of monoterpenoids differing in the number of double bonds and the pattern of their substitution were tested in the liquid-phase noncatalytic oxidation with nitrous oxide (N2O). The structure of olefins has a significant effect on the oxidation route. In the case of terpenoids containing 1,1-disubstituted double bond, nor-carbonyl compounds are formed with high selectivity.