Low-temperature 13C n.m.r. spectra allowed the observation of two different groups of signals, corresponding to the O,O-anti- and O,O-syn-rotamers, of a number of 2-acylfurans with the following alkyl groups bonded to carbonyl: Me, Et, Pri, But, pentan-3-yl. The ratios of these rotamers in dimethyl ether were thus obtained, and the barriers for the syn-anti interconversion were found to decrease with
低温13 C NMR谱允许的信号的两个不同组的观察,对应于O,O-抗-和O,O-顺-rotamers,一些2- acylfurans与烷基键合至羰基的以下:ME等,镨我,卜吨,戊-3-基。由此获得了这些旋转异构体在二甲醚中的比例,并且发现随着烷基的体积的增加,用于顺-反互转换的障碍减小。虽然分开13对于相应的2-酰基噻吩的旋转异构体,未检测到C信号,但是线增宽效应允许测量互转换垒。镧系元素对后一种衍生物(在1 H和13 C频率下)进行的位移实验表明,在所有所研究的2-酰基噻吩中,S,O-合成旋转异构体占主导地位。
Acylation Studies in the Thiophene and Furan Series. VI. Direct Acylation with Carboxylic Acids and Phosphorus Pentoxide
作者:Howard D. Hartough、Alvin I. Kosak
DOI:10.1021/ja01204a051
日期:1947.12
Simple Phase Transfer Catalytic Method for α-Methoxylation of Sterically Hindered Ketones
作者:E. Abele、K. Rubina、M. Shymanska、E. Lukevics
DOI:10.1080/00397919508013839
日期:1995.5
Reactions of sterically hindered ketones of ArylCOCHR(1)R(2) type (R(1), R(2) Me, Et, Ph) with carbon tetrachloride and methyl iodide in the presence of solid KOH and 18-crown-6 afford the corresponding alpha-methoxyketones [ArylCOC(OMe)R(1)R(2)] in one-pot process in 30-67% yields.
Abele, E. M.; Gol'dberg, Yu. Sh.; Popelis, Yu. Yu., Journal of Organic Chemistry USSR (English Translation), 1990, vol. 26, # 8, p. 1545 - 1550
作者:Abele, E. M.、Gol'dberg, Yu. Sh.、Popelis, Yu. Yu.、Shimanskaya, M. V.
DOI:——
日期:——
ABELE, EH. M.;GOLDBERG, YU. SH.;POPELIS, YU. YU.;SHIMANSKAYA, M. V., ZH. ORGAN. XIMII, 26,(1990) N, S. 1784-1790
作者:ABELE, EH. M.、GOLDBERG, YU. SH.、POPELIS, YU. YU.、SHIMANSKAYA, M. V.