Stereoselective dioxirane hydroxylations and the synthesis of tripod boronic acid esters
摘要:
Methyl(trifluoromethyl)dioxirane (TFDO, 1b), a powerful yet selective oxidant, was employed to achieve in high yield the direct stereoselective hydroxylation at tert-CH of cis,cis-1,3,5-trimethylcyclohexane (4), yielding triol 7 bearing all-axial disposition of the three OH groups. Similarly, TFDO oxidation of 1,3- and of 1,4-dimethylcyclohexane gave the corresponding Z-diols 5 and 6, respectively. Triol 7 was a convenient starting material to synthesize a novel borate-that is, 1-bora-2,8,9-trioxa-3,5,7-trimethyl-adamantane (8)-having a peculiar cage-shaped 'tripod' structure. From triol 7, novel tripod arylboronic Bronsted-assisted Lewis acids (BLA) could be obtained, as exemplified by 10a and 10b. (C) 2007 Elsevier Ltd. All rights reserved.
Selective C–H bond hydroxylation of cyclohexanes in water by supramolecular control
作者:Bin Yang、Jian-Fang Cui、Man Kin Wong
DOI:10.1039/c7ra03930a
日期:——
A new approach for selective hydroxylation of non-activated cyclohexanes using dioxirane generated in situ in water through supramolecularcontrol has been developed. Using β-CD and γ-CD as the supramolecular hosts, selective hydroxylation of cyclohexane substrates, including trans/cis-1,4-, 1,3- and 1,2-dimethylcyclohexanes and trans/cis-decahydronaphthalene, was achieved in up to 54% yield in water