Dissimilar reactivities of diastereomeric 1,1,1-trifluoro-3-(4-methoxyphenyl)-2,3-diphenylpropan-2-ols in an attempted elimination reaction
摘要:
Attempted dehydration of a diastereomeric mixture of 1,1,1-trifluoro-3-(4-methoxyphenyl)-2,3-diphenyl-propan-2-ols (6a) with thionyl chloride in the presence of pyridine afforded the rearranged derivative 8 as the main product and only small amounts of the expected olefins (4, 5). Similar treatment of (2RS,3RS)-6a gave the rearrangement product 8 exclusively, while transformation of (2RS,3SR)-6a resulted in the formation of compounds 4, 5 and 8. The different reactivity of the diastereomers is rationalised. (C) 2001 Elsevier Science B.V. All rights reserved.
Novel reactivity of tetracoordinate 1,2λ4-oxaselenetanes: oxirane formation reaction with retention of configuration
作者:Fumihiko Ohno、Takayuki Kawashima、Renji Okazaki
DOI:10.1039/a704277i
日期:——
Stable tetracoordinate 3-phenyl-1,2λ
4
-oxaselenetanes
give the corresponding oxiranes upon thermolysis; in sharp contrast to
CoreyâChaykovsky type reactions, oxirane formation proceeds with
retention of configuration, and the reaction can be recognised as a new
type of carbonâoxygen ligand coupling reaction of
λ
4
-selenanes.
Trifluoromethyl Ketones from Enolizable Carboxylic Acids via Enediolate Trifluoroacetylation/Decarboxylation
作者:Jonathan T. Reeves、Jinhua J. Song、Zhulin Tan、Heewon Lee、Nathan K. Yee、Chris H. Senanayake
DOI:10.1021/jo801737c
日期:2008.12.5
Primary and secondary (enolizable) carboxylic acids were converted in a single step to trifluoromethyl ketones. Treatment of the acid with 2.2 equiv of LDA generated an enediolate that was trifluoroacetylated with EtO2CCF3. Quenching the reaction mixture with aqueous HCI resulted in rapid decarboxylation and provided the trifluoromethyl ketone product in good yield. The process may be performed at -20 degrees C with a slight reduction in yield. The reaction was extended to the preparation of pentafluoroethyl and chlorodifluoromethyl ketones.
Experimental and Theoretical Evidence for Oxirane Formation Reaction of Pentacoordinate 1,2λ<sup>6</sup>-Oxathietanes with Retention of Configuration