rearrangements, and Baeyer–Villiger oxidation reactions were studied. In all cases, products were found, which resulted from cleavage of the amino-substituted cyclobutanebond, but not from the desired cleavage of the alternative alkyl-substituted cyclobutanebond. Two isoquinolones were prepared, to which an allenyl side chain was linked at position C4 via a stereogenic silyloxy-substituted carbon atom. Intramolecular
Stereoselective Synthesis of Chiral Polycyclic Indolic Architectures through Pd<sup>0</sup>-Catalyzed Tandem Deprotection/Cyclization of Tetrahydro-β-carbolines on Allenes
作者:Valérian Gobé、Xavier Guinchard
DOI:10.1002/chem.201500273
日期:2015.6.1
Enantioenriched N‐allyl tetrahydro‐β‐carbolines were prepared by chiral phosphoric acid‐catalyzed Pictet–Spengler reactions. The compounds undergo Pd0‐catalyzed cyclizationsthrough a tandemdeprotection/cyclization process. The regioselectivity of the attack is controlled by the chain length and by the substitution pattern of the allene function. Products resulting from 5‐exo‐ or 6‐exo‐attack were obtained
通过手性磷酸催化的Pictet-Spengler反应制备了对映体富集的N-烯丙基四氢-β-咔啉。这些化合物通过串联的脱保护/环化过程经历Pd 0催化的环化。攻击的区域选择性由链长和丙二烯官能团的取代模式控制。从5 exo-或6 exo-攻击获得的产物的非对映异构体比例高达95:5。Azepinopyrrido [3,4 b ]吲哚通过7-获得内切-cyclizations。
Enantioselective Synthesis of cis-Fused Cyclooctanoids via Rhodium(I)-Catalyzed [4 + 2 + 2] Cycloadditions
作者:Brendan C. Lainhart、Erik J. Alexanian
DOI:10.1021/acs.orglett.5b00267
日期:2015.3.6
o]-type cycloadditions offer efficient, atom-economical routes to diverse complexcarbocycles. Recently, such transformations have emerged as unique strategies for medium ring carbocyclesynthesis. Despite the important developments in this area, however, highly enantioselective [m + n + o]-type processes accessing medium ring carbocycles have yet to be developed. Herein, a rhodium-catalyzed [4 + 2 + 2]
催化多组分[ m + n + o ]型环加成化合物提供了高效,原子经济的途径,可通往各种复杂的碳环化合物。最近,这种转化已成为中环碳环合成的独特策略。尽管在该领域取得了重要进展,但是,高度对映选择性[ m + n + o进入中环碳环化合物的]型过程尚未开发。在本文中,报道了铑催化的烯丙二烯与丙二烯的[4 + 2 + 2]环加成反应,从而能够直接立体选择性地合成顺式融合的环辛烷类化合物。这些环加成成功地用于各种π组分,并证明了在[4 + 2 + 2]过程中高水平对映选择性的潜力。
Enantioselective Rhodium‐Catalyzed Dimerization of ω‐Allenyl Carboxylic Acids: Straightforward Synthesis of
<i>C</i>
<sub>2</sub>
‐Symmetric Macrodiolides
作者:Philip Steib、Bernhard Breit
DOI:10.1002/anie.201803369
日期:2018.5.28
Herein, we report on the first enantioselective and atom‐efficient catalytic one‐step dimerization method to selectively transform ω‐allenyl carboxylic acids into C2‐symmetric 14‐ to 28‐membered bismacrolactones (macrodiolides). This convenient asymmetric access serves as an attractive route towards multiple naturally occuring homodimeric macrocyclic scaffolds and demonstrates excellent efficiency
cis-Stereoselective nickel-catalyzed cyclization/alkylation and arylation reactions of allenyl-aldehydes and -ketones with organozinc reagentsElectronic supplementary information (ESI) available: typical procedures, NMR-data, and X-ray data. See http://www.rsc.org/suppdata/cc/b2/b207620a/
作者:Suk-Ku Kang、Seok-Keun Yoon
DOI:10.1039/b207620a
日期:2002.11.4
Highly stereoselective alkylative and arylative cyclization reactions of allenyl-aldehydes and -ketones with organozincreagents occur efficiently in the presence of catalytic Ni(COD)2 to afford cis-fused homoallylic cyclopentanols.