Oxidation by metal salts. X. One-step synthesis of .gamma.-lactones from olefins

Abstract

This paper describes a novel one-step synthesis of y-lactones by the reaction of manganic and other higher valenc metal carboxylates with readily available olefins and carboxylic acids. A free radical mechanism involving the selective generation and oxidation of organic free radicals is presented.As part of our studies on the oxidation mechanisms of metal carboxylates, we have observed' a novel reaction of manganic and ceric carboxylates with olefins leading to ybutyrolactones in excellent yields. This paper is intended to summarize our work on the development of this simple onestep synthesis of y-lactones from olefins and to establish the free radical mechanism for formation of these lactones.

Indirect Electroorganic Syntheses—A Modern Chapter of Organic Electrochemistry [New Synthetic Methods (59)]

“…In the case of secondary hydroxyl groups, the reaction leads to formation of (a-configurated alkenyl chlorides in one step [Eq. (69), (70) attached to a tertiary C-atom, then, depending on the reaction conditions, either formation of alkylidene dichlorides or rearrangement with formation of carbonyl compounds is 0 c 1…”

The Oxidation of Organic Compounds by Active Manganese Dioxide

“…A free-radical mechanism involving the selective generation and oxidation via organic free-radicals was presented. 139 Aldehydes can be conveniently prepared from their carboxylic acid esters via alcohols. Beginning, for example, from the ester 89 (ethyl 3-methoxybenzofuran-3-carboxylate), the aldehyde 91 (3-methoxybenzofuran-2-carbaldehyde) was obtained in 87% yield by manganese dioxide oxidation of the intermediate primary alcohol 90 In certain cases an IX,p-unsaturated alcohol on oxidation with active manganese dioxide has afforded a saturated cyclic keto-ether.…”

“…Thus. 100 mg of 51X-androstan-17 p-ol (139). stirred at room temperature in hexane (or acetonitrile) with manganese dioxide (2 g) for 20 h, gave pure 51X-androstan-17-one (140) The activity of manganese dioxide seems to be an important factor in the oxidation of the steroid alcohols.…”

Reactions with Manganese (III) Acetate

“…Rapid addition of the carboxyalkyl radical to the olefin. The reactivity of various olefins towards the carboxymethyl radical was studied by Heiba 23 …”

“…Olefin and Cyanoacetic Acid 23 The Mn(I1I) acetate mediated addition of cyanoacetic acid to an olefin is given in the next example. Owing to the large reactivity of cyanoacetic acid the reaction can be performed in acetic acid: 0.4 mol of cyanoacetic acid dissolved in 1 liter of acetic acid containing 10 % KOAc was reacted with 0.1 mol of Mn(OAch' 2H 2 0 and 0.2 mol of olefin at 50°C.…”