A new process for alkene formation. Photolysis of o-iodobiphenylyl ethers

Abstract

The o-iodobiphenylyl ethers 4, 5, 9, and 18 from cyclododecanol, 1-dodecanol, l,2:3,4-di-0-isopropylidene--D-galactopyranose, and l,2:5,6-di-0-isopropylidene-a-D-glucofuranose, respectively, were synthesized by tosylate (compounds 4, 5, and 9) or triflate (compounds 9 and 18) displacement by the anion of 2-iodo-4-phenylphenol. Alkene formation, which always was accompanied by formation of the unsubstituted biphenylyl ether (iodine replaced by hydrogen), resulted from photolysis of compounds 4, 5, and 9 in 2-methyl-2-propanol. Irradiation of 18 produced only the unsubstituted biphenylyl ether 19.

Synthesis of deoxyhalogeno sugars. Reaction of halide ions with 1,2,3,4-tetra-O-acetyl-6-O-[(trifluoromethyl)sulfonyl]-.beta.-D-glucopyranose

“…These spectra, in addition to exhibiting all the proper absorptions, differed significantly only in absorptions for H-6, H-6', and C-6. As a further confirmation of these structural assignments (5)(6)(7)(8) the following melting point comparisons were made: 5, mp 150-153 °C (lit.13 mp 148 °C); 6, mp 125-127 °C (lit.14 124-125 °C); 7, mp 113-115 °C (lit.16114-115 °C); 8,126.5-127.5 °C (lit.16…”

“…It allowed formation and isolation of the triflate 2, a compound that was stable in solution at room temperature in the absence of nucleophiles and could be stored indefinitely at -20 °C. The triflate 2 reacted readily with halide ions to produce the corresponding deoxyhalogeno sugars [5][6][7][8]. Separation of the triflate 2 from the base 4 required chromatography, a process that caused some triflate decomposition; thus, although 2 is isolable, the optimum yields of 5-8 were obtained when it (2) was reacted, without isolation, in the flask in which it was generated.…”