Catalytic dehydrogenative dual functionalization of ethers: dealkylation–oxidation–bromination accompanied by C–O bond cleavage via aerobic oxidation of bromide
A catalytic dehydrogenative dual functionalization (DDF) of ethers viaoxidation, dealkylation, and α-bromination by the aerobic oxidation of bromide was developed to obtain the corresponding α-bromo ketones in high yields. In particular, the reaction of substituted tetrahydrofurans as cyclic ethers provided 3,3-dibromo tetrahydrofuran-2-ols in high yields selectively through the double α-bromination
BENZYLATION OF ALCOHOLS TO BENZYL ETHERS WITH ALKALI CATION EXCHANGED Y TYPE ZEOLITE
作者:Makoto Onaka、Motomitsu Kawai、Yusuke Izumi
DOI:10.1246/cl.1983.1101
日期:1983.7.5
Benzylation of alcohols with benzyl chloride is found to proceed efficiently in the presence of alkali cation exchanged Y type zeolite in a non-polar solvent under neutral conditions. The effects of solvent and alkali cation of zeolite are studied.
Zeolite-promoted benzylation of alcohols with benzyl chloride has been investigated. By use of a series of cation-exchanged zeolites, which have the same crystalline structure but different acid and base properties, it is confirmed that the cooperative function of acid sites and base sites of zeolite is required for the effective benzylation of alcohols although both acid and base strengths are low. It is also found that alcohols show different reactivities in zeolite from those in solution depending on their molecular structures because the benzylation is promoted inside the narrow cavities of zeolite.
Visible-Light-Promoted Conversion of Alkyl Benzyl Ether to Alkyl Ester or Alcohol via O-α-sp<sup>3</sup> C–H Cleavage
作者:Ping Lu、Tianyuan Hou、Xiangyong Gu、Pixu Li
DOI:10.1021/acs.orglett.5b00663
日期:2015.4.17
A mild and high-yielding visible-light-promoted conversion of alkylbenzylethers to the alkyl esters or alkyl alcohols was developed. Mechanistic studies provided evidence for a radical chain reaction involving the homolytic cleavage of O-α-sp3 C–H bonds in the substrate as one of the propagation steps. We propose that α-bromoethers are key intermediates in the transformation.
Bismuth bromide-catalyzed reductive coupling of carbonyl compounds and its application to the synthesis of novel crownophanes
作者:Naoki Komatsu、Jun-ya Ishida、Hitomi Suzuki
DOI:10.1016/s0040-4039(97)01720-6
日期:1997.10
The reductive homocoupling of carbonylcompounds and heterocoupling of a carbonylcompound with an alkoxysilane were both effected smoothly with triethylsilane in the presence of a catalytic amount of bismuth bromide (1–3 mol%) under mild conditions. This ether-forming reaction was successfully applied to the single-step preparation of novel crownophanes with olefinic or acetylenic linkages.