281665-93-8

Upstream product

• 4885-02-3 Dichloromethyl methyl ether 
• 132098-46-5 1,5-bis(5-tert-butyl-2-methoxyphenyl)pentane 

Relevant academic research and scientific papers

Medium-sized cyclophanes. Part 52: Synthesis and structures of [2.n] metacyclophane-1,2-diones

A series of syn- and anti-[2.n]metacyclophan-1-enes, 3, and [2.n]metacyclophane-1,2-diols, 4, were prepared in good yields by a McMurry cyclization of 1,n-bis(5-tert-butyl-3-formyl-2-methoxyphenyl)alkanes, 2. Upon increasing the length of the methylene bridge higher yields of 3 were obtained. The assignment of the syn and anti conformations has been confirmed by 1H-NMR analyses. The 1,2-diol derivatives 4 were converted to the 1,2- diones 9 by Swern oxidation. However, [2.2]metacyclophane-1,2-dione, 9a, was found to be quite labile under treatment by silica gel column chromatography and on refluxing in toluene to give the dicarboxylic acid 10 in quantitative yield. Thus, a trapping reaction of diketone 9a was attempted, in which the crude diketone 9a was treated with o-phenylenediamine in ethanol at room temperature for 24 h to afford in almost quantitative yield the desired [2.2]metacyclophane 11 having a quinoxaline skeleton. Similarly, in the case of [2.3]- and [2.4]metacyclophanes, Swern oxidation of the trans-diols trans- 4b,c also afforded the desired diketones 9b,c in quantitative yields as stable yellow prisms.

Medium-size cyclophanes, 771 Synthesis and addition of bromine to syn-[2.n]meta-cyclophan-1-enes

McMurry cyclisation of 1,n-bis(3-formyl-2-methoxyphenyl)alkanes afforded syn-dimethoxy[2.n]metacyclophan-1-enes, in which cis-addition of bromine to the bridged double bond in CH2Cl2 was observed.