A general route to α-alkyl (E)-α,β-unsaturated aldehydes
作者:Nour Lahmar、Jamaa Aatar、Taïcir Ben Ayed、Hassen Amri、Moncef Bellassoued
DOI:10.1016/j.jorganchem.2006.03.015
日期:2006.6
Bis(trimethylsilyl)-tert-butylaldimines 3 react with aldehydes in the presence of zinc bromide at room temperature to give, after hydrolysis, the desired α-alkyl α,β-ethylenic aldehydes in good yield and with very high Estereoselectivity. The reaction was believed to proceed via the α-silyl β-siloxyimines 4.
A Synthetic Methodology for Pyrroles from Nitrodienes
作者:Mohamed A. EL-Atawy、Francesco Ferretti、Fabio Ragaini
DOI:10.1002/ejoc.201701814
日期:2018.9.16
Palladium complexes containing the ligand 4,7‐dimethoxy‐1,10‐phenanthroline catalyze the reductivecyclization of nitrodienes using carbonmonoxide as the reductant to give pyrroles. Carbon dioxide is the only stoichiometric byproduct of the reaction.
A chiral variant of B(C6F5)3 with a 3,3′‐disubstituted binaphthyl backbone is shown to catalyze Nazarov cyclizations with high levels of enantio‐ and diastereocontrol. The parent B(C6F5)3 also promotes these ring closures efficiently. This electrocyclization is another example of the still small family of C−C bond formations mediated by B(C6F5)3 as the catalyst.
具有3,3'-双取代的联萘骨架的B(C 6 F 5)3的手性变异体可催化Nazarov环化反应,并具有高水平的对映和非对映控制。母体B(C 6 F 5)3也有效地促进了这些环的闭合。这种电环化是由B(C 6 F 5)3作为催化剂介导的C-C键形成家族仍然很小的另一个例子。
Copper-Catalyzed Stereospecific Hydroboration of Internal Allylic Alcohols
作者:Enhui Ji、Haiwen Meng、Yue Zheng、Velayudham Ramadoss、Yahui Wang
DOI:10.1002/ejoc.201901435
日期:2019.11.30
Copper‐catalyzed highly stereospecific hydroboration of internal allylic alcohols using a silyl ether transient protection strategy is reported. This in situ protection effectively avoids the preferential side reaction of free hydroxyl group with boron reagent, thus promoting hydroboration. This method provides both the anti‐ and the syn‐ diastereomers of 1,3‐diols in high level of diastereomeric ratios
Copper-Catalyzed Tandem Hydrocupration and Diastereo- and Enantioselective Borylalkyl Addition to Aldehydes
作者:Won Jun Jang、Jaesook Yun
DOI:10.1002/anie.201806937
日期:2018.9.10
report the copper‐catalyzed stereoselective addition of in situ generated chiral boron‐α‐alkyl intermediates to various aldehydes including α,β‐unsaturated aldehydes under mild conditions. This tandem and multicomponent method facilitated the synthesis of enantiomerically enriched 1,2‐hydroxyboronates bearing contiguous stereocenters in good yield with high diastereo‐ and enantioselectivity up to a ratio