The intramolecular cyclization of (-)-cis-carveol under iodine treatment afforded (1R,5R,6S)-6-iodomethyl-2,6-dimethyl-7-oxabicyclo[3.2.1]oct-2-ene that was subjected to allyl oxydation with the complex CrO 3 DMP giving a synthetically valuable building block, (1R,5R,6S)-6-iodomethyl-2,6-dimethyl-7-oxabicyclo[3.2.1]oct-2-ene-4-one. In the latter the double bond was cleaved by ozonization to obtain the expected trioxo derivative, and the subsequent ozonolysis of its enol form provided a multiple functionalized tetrahydrofuran derivative.
Sterical loading, topology, and the character of the organic molecule functionalization sometimes lead to the "uncommon" course of typical reactions with its participation. One of such compounds is epoxycyclohexanone I that we have recently described [1].Our attempts to convert it into hydroxycyclohexanone II by ozonolysis under the conditions of Criegee rearrangement [2, 3] resulted only in diketone III [1] inert with respect to m-chloroperbenzoic acid. We also failed to perform the oxidative cleavage of epoxyalcohol IV by treating with HIO 4 , we obtained only diol V. At the reduction of epoxyalcohol IV with LiAlH 4 alongside the expected diol VI we isolated regioisomeric diols VII and O O O OH O O O O O 3 I II III HO O IV NaBH 4 HO OH V HIO 4 THF _ H 2 O m-ClC 6 H 4 CO 3 H VIII. Usually the reduction with LiAlH 4 of trisubstituted epoxides provides a tertiary alcohol. The assignment of stereoisomeric diols VII and VIII was done based on the characteristic doublets of H 3 in the 1 H NMR spectra. Whereas for 2,3-trans-isomer VII J 3,2 is 11.2 Hz [δ(H 3 ) 3.30 ppm], in the isomer VIII J 3,2 is 5.2 Hz [δ(H 3 ) 3.51 ppm] (analogous examples have been described in [4]). For further identifi cation diol VIII was converted into diacetate IX. HO OH VI, 33% IV HO OH HO VII, 27% VIII, 7% OH AcO OAc Ac 2 O _ Py IX + LiAlH 4 THF, Δ +Thus except for the reduction of the epoxyketone I with sodium borohydride into alcohol IV the other reactions of these compounds proceeded by unexpected routes or with the partial formation of abnormal products.(1R,3R,5S)-4,4-Dimethyl-5-isopropenyl-2-methylidenecyclohexane-1,3-diol (V). To a solution of 0.08 g (0.41 mmol) of compound IV in 5 ml of the mixture
The oxidation of (1S,5R,7R,S)-(4,7-dimethyl-6-oxabicyclo[3.2.1]oct-3-en-7-yl)methanol epimeric at the C 7 atom resulted in scalemic (5R)-5-acetyl-2-methylcyclohex-2-en-1-one.
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