AN ALDOL-TYPE REACTION OF ACTIVE METHYL GROUPS OF NITROGEN-CONTAINING HETEROAROMATIC COMPOUNDS
作者:Hiroshi Hamana、Tsutomu Sugasawa
DOI:10.1246/cl.1983.333
日期:1983.3.5
Active methyl groups of nitrogen-containing heteroaromatic compounds react with benzaldehydes in the presence of 9-BBN triflate and diisopropylethylamine in dichloromethane to give the corresponding aldol-type products under mild conditions.
and efficient visible light induced Meerwein hydration reaction of alkenes in aqueous medium using mpg-C3N4 as a recyclabe photocatalyst has been disclosed. This protocol provides a direct approach for the preparation of racemic alcohols via a free radical mechanism. Water acted as both a solvent and a reagent without any additives or co-solvents. The metal-free heterogeneous semiconductor is found
已经公开了使用mpg-C 3 N 4作为可回收的光催化剂,绿色和有效的可见光诱导的水性介质中烯烃的Meerwein水合反应。该协议提供了一种通过自由基机制制备外消旋醇的直接方法。在没有任何添加剂或助溶剂的情况下,水既充当溶剂又充当试剂。发现不含金属的异质半导体至少可以完全回收5次,而活性没有任何显着降低。Meerwein水合反应具有出色的底物范围,并以中等至高收率提供了所需的产物。此外,该反应可以在太阳光照射下进行,并且可用于大规模反应,并具有令人满意的结果。
General Method for an Aldol-Type Reaction of 2-Methylbenzothiazole with Carbonyl Compounds
A general and versatile method for the preparation of a variety of β-hydroxybenzothiazoles (aldol-type adducts) by the reaction of α-lithio-2-methylbenzothiazole with carbonyl compounds was proposed. As an example of the use of α-lithio-2-methylbenzothiazole as a masked enolate, the product obtained by the reaction of this lithium reagent with 5-chloro-2-pentanone could be effectively transformed into the corresponding β-oxyaldehyde [2-methyl-2-(2-oxoethyl)-tetrahydrofuran].
Iridium-Catalyzed Asymmetric Borylation of Unactivated Methylene C(sp<sup>3</sup>)–H Bonds
作者:Ronald L. Reyes、Tomohiro Iwai、Satoshi Maeda、Masaya Sawamura
DOI:10.1021/jacs.9b01952
日期:2019.5.1
Herein, we show the highly enantioselective borylation of unactivated methylene C(sp3)-Hbonds in 2-alkylpyridines and 2-alkyl-1,3-azole derivatives using an iridium-BINOL-based chiral monophosphite catalyst system. Quantum chemical calculations using the artificial force induced reaction (AFIR) method suggested that a monophosphite-Ir-tris(boryl) complex generates a narrow chiral reaction pocket where
Benzothiazole-Directed Enantioselective Borylation of Secondary Benzylic C–H Bonds Using Iridium Catalysis
作者:Lili Chen、Senmiao Xu、Liang-Jun Xie
DOI:10.1055/a-2335-8677
日期:2024.9
enantioselective secondary benzylic C–Hborylation using benzothiazole as the directing group. Various monosubstituted 2-arylalkylbenzo[d]thiazole were well-tolerated, affording the corresponding products in moderate to good yields with good enantioselectivity. The C–B bond in one borylated product could undergo stereospecific transformations to form a series of C–C and C–heteroatom bonds.