Oxymercuration-demercuration and hydroboration-oxidation of endo-dicyclopentadiene (endo-tricyclo[5.2.1.02,6]deca-3,8-diene)

Abstract

hexanone was slowly added and the resulting mixture was stirred for 24 hr at 0°. Then water was added (10-15 ml) slowly to decompose the excess hydride and to hydrolyze the reaction mixture. The boronic acid formed was oxidized by adding 66 ml of 3 N sodium hydroxide followed by dropwise addition of 66 ml of 30% hydrogen peroxide (vigorous reaction). The resulting mixture was stirred at 30-50°for 1 hr. Then the reaction mixture was extracted five times with 60-ml portions of ether and the ether extract was washed five times with equal amounts of ice water to remove diglyme. The ether extract was dried over magnesium sulfate. After the solvent was removed, the mixture was distilled at 20 mm to remove cyclohexanol (from the oxidation). The pressure was then reduced to obtain 27 g (99%) of 2-cyclohexylcyclohexanol (cis 96% by glpc analysis on a TCEP column), bp 117-118°( 6 mm), mp 59-61°, p-nitrobenzoate mp 112-114°(lit.21 mp 61°, p-nitrobenzoate mp 113°).B. Preparation of czs-2-Phenylcyclopentanol. To a solution of 150 ml (150 mmol) of a 1.0 M solution of disiamylborane in THF in a 500-ml flask maintained at 0°under nitrogen was added 14.4 g (90 mmol) of 2-phenylcyclopentanone over a period of 15 min. The resulting mixture was stirred at 0°for 24 hr and then worked up as usual. The volatile solvents and siamyl alcohol were removed at 40-45°(10 mm). Distillation of the residue yielded 11 g (75%) of 2-phenylcyclopentanol (cis 97% by glpc), bp 118°( 8 mm), n20o 1.5433, p-toluenesulfonate mp 96-97°[ lit.22 pure cis isomer, bp 111-113°(5 mm), n20d 1.5460, p-toluenesulfonate mp 97-98°].

Oxymercuration-demercuration and hydroboration-oxidation of endo-tricyclo[5.2.2.02,6]undeca-3,8-diene. Stereospecific oxymercuration leading to the 4-exo-hydroxy derivative

“…34 The oxymercuration of the diene 1 can be contrasted to that of endo-dicyclopentadiene, a lower homolog of 1. endo-Dicyclopentadiene gave a mixture of 8-and 9-exohydroxy-endo-tricyclo[5.2.1.02,6]dec-3-ene as sole products. 22,26,27 The result is in complete agreement with what is expected from the oxymercuration reaction of norbornene. 25,28 Norbornene has been shown to undergo oxymercuration quite rapidly, yet with exo cis addition mechanism.…”

“…Scheme II). The structure of 1218 was proven by Jones oxidation of the mixture of 10, 11, and 12 obtained above, whereby 12 was converted to tricyclo[5.2.2.02 '6]undecan-3-one (22) which was identical with the specimens prepared by hydroboration-sodium dichromate oxidation of 9 (Scheme IV) as well as by hydrogenation of 6.…”

Hydroboration-Oxidation of (±)-(1α,3α,3aβ,6aβ) -1,2,3,3a,4,6a-Hexahydro-1,3-pentalenedimethanol and Its O-Protected Derivatives: Synthesis of New Compounds Useful for Obtaining (iso)Carbacyclin Analogues and X-ray Analysis of the Products

“…Such isomerizations between alkyl-boranes are known in the literature [ 33 , 34 , 35 , 36 , 37 ]. The α- or β-configuration of the hydroxyl groups introduced is not important, because the OH is oxidized in the next step to a ketone.…”

Synthesis and phospholipase C inhibitory activity of D609 diastereomers

“…Racemic diastereomeric alcohols 5-8 were obtained following described procedures: O-exo,C-exo 5 (15); O-endo,C-exo alcohol 6 (16,17); O-exo,C-endo 7 (18); and O-endo,C-endo 8 (15,17,18) and characterized by comparison with reported spectroscopic data (17). FTIR spectra are reported in cm −1 .…”

“…General procedure for the synthesis of potassium xanthates (1)(2)(3)(4)(14)(15)(16)(17). The alcohol (1.1 eq) was slowly added to a solution of t-BuOK (1 eq.)…”