Electron transfer photoinduced cleavage of acetals. A mild preparation of alkyl radicals
摘要:
Electron transfer from 2-alkyl- and 2,2-dialkyldioxolanes as well as from open-chain ketals to singlet excited benzene-1,2,4,5-tetracarbonitrile (TCNB) is followed by fragmentation of the donors radical cation to yield alkyl radicals and dialkoxy carbocations. The first species are trapped by TCNB to yield alkylbenzenetricarbonitriles (substitution of a second cyano group can be obtained sequentially) and in a minor path are reduced to alkanes, while the latter ones react with nucleophiles to give ortho acid derivatives. In view of the results of radical clock experiments, it is assumed that part of the process is a concerted (radical cation cleavage-addition to the aromatic) reaction, while another part involves the free-radical cation. On the other hand, intersystem crossing from the singlet radical ion pair to the triplet manifold causes cleavage of the acetal to the corresponding carbonyl derivative. This reaction offers a mild method for the preparation of alkyl radicals via C-C bond cleavage.
Visible-Light-Induced Acetalization of Aldehydes with Alcohols
作者:Hong Yi、Linbin Niu、Shengchun Wang、Tianyi Liu、Atul K. Singh、Aiwen Lei
DOI:10.1021/acs.orglett.6b03403
日期:2017.1.6
have achieved a simple and general method for acetalization of aldehydes by means of a photochemical reaction under low-energy visible light irradiation. A broad range of aromatic, heteroaromatic, and aliphatic aldehydes have been protected under neutral conditions in good to excellent yields using a catalytic amount of Eosin Y as the photocatalyst. Our visible light mediated acetalization strategies are
Alkyl Acetal Compound, Process for Producing the Same, and Lubricating Oil Composition
申请人:Sato Haruhito
公开号:US20080234152A1
公开(公告)日:2008-09-25
A compound which satisfies requirements for the annealing property and the lubricating property simultaneously and a process for producing the compound are provided. The compound is an alkylacetal compound represented by the following general formula (1) or (2). In the general formulae, R
1
and R
2
represent hydrocarbon groups, R
3
to R
8
represent hydrogen atom or hydrocarbon groups, i and j represent integers satisfying the relation that the sum of the integers is 8 to 98, and k represents 0 or 1.