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。
Cobalt‐Catalyzed Regio‐ and Stereoselective Hydroboration of Allenes
作者:Can Li、Zheng Yang、Lei Wang、Yinlong Guo、Zheng Huang、Shengming Ma
DOI:10.1002/anie.201915716
日期:2020.4.6
pincer-ligand-based cobalt-complex-catalyzed allenehydroboration affording Z-allylic boronates is described. The reaction demonstrates an excellent regio- as well as Z-stereoselectivity and a wide substrate scope that tolerates many functional groups. Based on solvent-assisted electrospray ionization mass spectrometry (SAESI-MS) studies, a rationale for the cobalt-catalyzed hydroboration involving the highly selective
Synthese regiospecifique d'allenes terminaux a partir de propargyltrimethylsilanes simples ou fonctionnels
作者:J. Pornet、D. Damour、L. Miginiac
DOI:10.1016/s0022-328x(00)99606-2
日期:1987.1
Protodesilylation of varied propargyltrimethylsilanes, using boron trifluorideacetic acid as reagent, give regiospecifically terminal allenes with very good yields. Yet, particular ω-functional propargyltrimethylsilanes may lead to vinylsilanes resulting from a ring-closing cyclisation reaction.
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
hydrosilylation of allenes with primary and secondary phenylsilanes. It shows high selectivity towards the production of branched allylsilanes with a wide range of allenes. It is worth mentioning that the catalytic loading of the palladium can be reduced to 500 ppm. This work opens a new front of using bidentate thiophene ligand as a reaction promoter in transition‐metal‐catalyzed organic reaction.