Catalytic One‐Pot Osmylation of Cyclohexadienes: Stereochemical and conformational studies of the resulting polyols

Abstract

' ) Physikalische Abteilung, Cibu-tieigy A t i , CH4002 Base1 (8.1V.92) Catalytic double osmylation is described for a series of cyclohexadienes in acetone/H,O in the presence of the co-oxidant ~'-methylmorpholine N-oxide (NMO). The formation of polyols occurred stereospecifically with cyclohexadienes 3,7, and l l a , leading thereby to tetrols 5a, and 9a and to alio-inositol(14a), respectively. To the contrary, trans-cyclohexadiene-diol 15a gave a mixture of the stereoisomeric inositols 18a (epi), 19a (nro), and 20a (chiro). High-field NMR let to clearcut conformational analyses of the polyhydroxylated derivatives.Introduction. ~ In a preliminary communication, we described the one-pot double catalytic osmylation of dihydropyridine 1 which led stereospecifically to the aminodideoxyaltrose derivative 2 [ 11. The stereospecific 'cisltranslcisltrans' outcome of this multistep reaction -which led in good yield to 5 asymmetric centres ~ is most probably due to minimization of steric interactions during each osmylation step. Due to the strong anomeric effect, which is more pronounced in piperidinoses than in pyranoses, compound 2 occurred exclusively in the chair conformation [ 11.

Polyols as Templates for the Synthesis of Macrocycles from Boronic Acid Building Blocks

“…In analogy to the tetrahydroxylation of 1,4-cyclohexadiene by osmium tetroxide, [23] 2 could be obtained in good yield. For better isolation, the tetraol 2 was first acetylated, purified as the tetraester 1 and then hydrolyzed to give pure tetraol 2 in 79 % overall yield.…”

Selective aliphatic carbon–hydrogen bond activation of protected alcohol substrates by cytochrome P450 enzymes

“…52 Cyclohexenediols are usually synthesised from cyclohexadienes. 53,54 Cyclohexane turnover has been investigated with WT P450cam and the Y96A mutant. Both gave low levels of cyclohexanol as the main product with the Y96A mutant also producing some of the further oxidation product, cyclohexanone.…”

Benzoate dioxygenase fromRalstonia eutrophaB9 – unusual regiochemistry of dihydroxylation permits rapid access to novel chirons

“…Synthesis of (5R,6R)-2,2-dimethyl-1,3-dioxaspiro [4.5]decan-6ol (26). To a stirred solution of 25 (1.72 g, 5.72 mmol) in THF (50 mL) at −78 °C, was added dropwise tetrabutylammonium fluoride (1.0 M solution in THF, 5.72 mL, 2.0 equiv.)…”