A FACILE OXIDATIVE LACTONIZATION OF 1,ω-Diols WITH SODIUM BROMITE

Abstract

A practically useful method for the oxidation of 1,ω-diols to lactones is described. The scope and limitations are also presented.

Iridium-Catalyzed Oxidative Dimerization of Primary Alcohols to Esters Using 2-Butanone as an Oxidant

“…To date, various reaction systems have been developed, which include stoichiometric oxidation using Na 2 Cr 2 O 7 , 3 Br 2 -HMPT, 4 Ca(OCl) 2 , 5 NaOCl, 5 NaBrO 2 , 6 NaBrO 3 -NaHSO 3 , 7 PCC-Al 2 O 3 , 8 and so on. Recently, Bobbitt et al reported oxidative dimerization of polyfunctional primary alcohols using oxoammonium salts.…”

Potential intermediate, (±)-di-o-acetyl-3α-phenylselanyl-3,3a-dihydro-B-nor-6,7a-secolycorin-5-one for synthesis of the Amaryllidaceae alkaloid lycorine: formal and total syntheses of (±)-lycorine

“…To retard the undesired reaction, the reaction of compound 11 was conducted with dihydropyran (DHP) to give a tetrahydropyran-2-yl ether 13, which was readily dehydroiodated with DBU to furnish olefin 14. Furthermore, deprotection of ether 14 with p-TsOH in CH,C12-MeOH gave in 78% overall yield (from iodo lactone 11) 6-lactone alcohol 15, Jones oxidation of which in acetone afforded 6-lactonic acid 16 in 63% yield. ?…”

“…To confirm this assumption, conversion of lactone 16 into a known y-lactam 19 was performed. Thus, compound 16 was transformed into an azide in the usual manner (ClCO,Et, Et,N; NaN,, water) followed by Curtius rearrangement with benzyl alcohol in boiling toluene to give the benzyl carbamate 17 in 72% yield. Reductive debenzylation of carbamate 17 and successive acid treatment afforded amino ester 18, which was heated in EtOH for 10 h to furnish lactam 19 in 86% yield (Scheme 3).…”

“…For synthesis of ( k )-lycorine, introduction of functional groups on the C ring in acid lactone 16 was the next important step. The tert-butyl carbamate 21 rather than the benzyl carbamate 17 seemed to be a potential candidate for transformation into functionalized y-lactam have reported that epoxidation of latrimethysiloxy-2,3-didehydrolycorane proceeded only from the p-face.…”

Effective direct esterification of butanol by eco-friendly Preyssler catalyst, [NaP5W30O110]14−

“…Several methods for the dimeric esterification of primary alcohols, such as benzyltrimethylammonium tribromide in carbon tetrachloride, bromine-potassium bromate in water, sodium hypochlorite in acetic acid, sodium dichromate-sulfuric acid, calcium hypochlorite in acetonitrile-acetic acid, and sodium bromite in acetic acid have been employed for this propose [1][2][3][4][5].…”