[reaction: see text] An efficient three-component coupling of aldehyde, alkyne, and amine to generate propargylamines has been effected under microwave irradiation in water using only CuI catalyst without the noble metal cocatalyst. This method has proved to be applicable to a wide range of substrates. In addition, the preliminary experiment using (S)-proline methyl ester as a chiral source demonstrated that it could be developed to be a direct and highly diastereoselective method for construction of chiral propargylamines.
[reaction: see text] A rapid and direct amination of aryl halides has been developed in good to high yields under microwave irradiation without a transition-metal catalyst. This reaction is a particularly powerful method for the coupling of electron-rich aryl halides with various amines. In some cases, the excellent regioselectivity could be observed, which facilitated the preparation of meta-substituted anilines from ortho- or para-substituted phenylhalides. In addition, a mechanism via the interesting benzyne intermediate has been proposed.
An unusual thermophilic bacterium has been isolated from deep subsurface sediments and tested for its ability to enhance Fe (m), Co (m>, and Cr (Vi) reduction. Without the * bacterium, abiotic metal reduction was insignrfcant at temperams below 45OC but became a major process at 75OC. Addition of the bacterium enhanced the reduction of these metals up to fourfold. This study demonstrates abiotic and biotic metal reduction under organicrich thermic conditions and suggests that thermally and/or biologically enhanced metal reduction may provide an alternative for remediating metal contamination.
[reaction: see text] A short and unique approach to (+/-)-lycoramine as one of the galanthamine-type alkaloids has been efficiently developed. The alternative advantage lies in that three stereocenters, including a crucial quaternary carbon center, were constructed with high diasteroselectivity via a key one-step NBS-mediated semipinacol rearrangement of the allylic alcohol.
Over the past decade, the effectiveness of i-PrMgCl·LiCl has been constantly highlighted by a number of research groups. Its enhanced nucleophilicity brings prosperity to highly functionalized Grignard reagents, other useful bimetallic (alkali-metal) agents and nucleophilic alkylation products under mild reaction conditions. In this feature article, a comprehensive, systematical and in-depth overview of i-PrMgCl·LiCl is provided in a multidisciplinary idea. It involves the structural and kinetic perspectives of i-PrMgCl·LiCl as well as its unique reactivity and selectivity, with knowledge of the former helping to rationalize trends of the later.
A new method for intermolecular sp3-sp3 C-C bond formation between primary aliphatic alcohol and olefin by use of a RhCl(PPh3)3 (cat.)/BF3.OEt2 (2.5 equiv)/BuBr (0.5 equiv)/toluene system was first disclosed, which possessed quite significant utilities for organic synthesis, especially for that of secondary alcohols. The most significant aspect is the discovery that rhodium-catalyzed C-H bond activation of alcohols is feasible under Lewis acid-promoted conditions.
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