Corey lactone

The Baeyer-Villiger oxidation is a synthetically very useful reaction it is for example often used in the synthesis of natural products. The Corey lactone 11 is a key intermediate in the total synthesis of the physiologically active prostaglandins. It can be prepared from the lactone 10, which in turn is obtained from the bicyclic ketone 9 by reaction with m-chloroperbenzoic acid (MCPBA) " ... 

In addition to its other properties, interest in the potential use of the vasodilative properties of prostaglandin El, alprostadil ( ), has led to several conceptually different syntheses.For this purpose, the classic Corey process has to be modified by reversing the order of addition of the side chains to allow for convenient removal of the unwanted double bond in the upper side chain. For example, Corey lactone is protected with dihydropyran (acid catalysis), reduced to the lactol with diisobutyaluminum hydride, and then subjected to the usual Wittig reaction to give intermediate This is... 

Retrosynthetic cleavage of the A13,14 double bond in 6 significantly simplifies the side-chain appendage attached to C-l2 and affords aldehyde 7 and ketophosphonate 8 as potential precursors. In the synthetic direction, a Homer-Wadsworth-Emmons reaction10 would appear to provide a very simple means of joining intermediates 7 and 8 with concomitant formation of the requisite trans C13-C14 olefin. Retrosynthetic simplification of aldehyde 7 provides intermediate 9, a molecular assembly commonly known as the Corey lactone. 

PGF2a- The cyclopentane ring of the Corey lactone (9) is the host of four contiguous stereogenic centers. Retrosynthetic simplification of 9 provides 10, a construct which is more complex than 9 Nevertheless, intermediate 10 possesses structural features that satisfy the requirement for the iodolactonization transform. The iodolactone in 10 constitutes the retron for the iodolactonization transform.11 Cleavage of the indicated bonds in 10 sacrifices two of the five stereocenters and provides unsaturated carboxylic acid... 

Corey procedure 243 Corey lactone 68 ff., 72 f. Corey-Nicolaou... 

The catalyst played an important role in the asymmetric synthesis of Corey lactone based on high diastereofacial selective Diels-Alder reaction between chiral acrylate 37 and 5-benzyloxymethylcyclopentadiene [41] (Equation 3.9). The cycloadduct 38 was then converted into chiral Corey lactone [42] by a three-step procedure. 

CCuN 544-92-3) see Cinoxacin Citalopram Lamotrigine Mabuterol Methallenestril Trimetrexate glucuronate Corey lactone... 

Ci,)Hij,N02 143343-85-5) see Dolasetron mesilate l,2,3,7,8,8a-hexahydro-6-hydroxy-5-mcthoxy-l-methyl-cyclopent[i7]isoquinolinc<7-carboxaldehyde (C14H17NO3 5S09i-59-7) see Glaziovine (3au,4a,5p,6aa)-(-)-hexahydro-4-(hydroxymethyI)-2-oxo-2//-cyclopentaf lfuran-5-yl l,l -biphcnyl-4-carboxylate see under Corey lactone... 

The Baeyer-Villiger reaction has found considerable application in the synthesis of prostaglandins. One common pattern involves the use of bicyclo[2.2.1]heptan-2-one derivatives, which are generally obtained by Diels-Alder reactions. For example, compound 10 is known as the Corey lactone and has played a prominent role in the synthesis of prostaglandins.237 This compound was originally prepared by a Baeyer-Villiger oxidation of 7-(methoxymethyl)bicyclo[2.2.1]hept-5-en-2-one.238... 

Another example of a case where acid-base chemistry competes with cyclization is found in efforts to construct an analog of the Corey lactone [45], The enantiomerically pure unsaturated ester 91 was assembled and subjected to the conditions indicated in Eq. (26). In this instance, dimethyl methylmalonate was used as the proton donor to avoid 1,4-addition of the conjugate base to 91. Cyclization afforded a combined 77% isolated yield of the y-hydroxy ester 92 and the lactone 93 the former could be converted to the lactone in the... 

Amputch MA, Little RD (1991) Tetrahedron 47 383. Utley JHP, (1987) Electrogenerated bases. In Steckhan E (ed) Topics in current chemistry. Springer, Berlin Heidelberg New York, p 133 Little RD, Sowell CG (1991) Stereoselection in electroreductive cyclization. Construction of a Corey lactone precurser. In Little RD, Weinberg NL (eds) Electroorganic synthesis, festschrift for Manuel M. Baizer. Dekker, New York, p 323 Shono T, Mitani M (1971) J. Am. Chem. Soc. 93 5284... 

The author next tried to stabilize the PGI2 structure by introducing second fluorine atom to the 7-position. However, it had been unknown to make such a difluorovinyl ether unit in the literature. We studied difluorination and Wittig reaction as key steps in the synthetic route of the target difluoro-PGl2 from the Corey lactone. After searching the difluorination reaction, it was found that fluorination with A/-fluorobenzenesulfonimide in the presence of potassium bis(trimethylsilyl) amide and manganese dibromide effectively provided the desired difluoride (Table 7) [106]. 

The synthesis of AFP-07 is shown in Scheme 9 [107], The enone 59 prepared from the Corey lactone was reduced with aluminum reagent and protected with f-butyidimethylsilyl chloride. Fluorination of the lactone 60 under the standard conditions gave the difluorolactone 61. The carbonyl group of the difluorolactone... 

Reaction of the anion from phosphonate (5-1) with ethyl meta-triflurophenoxy-methylacetate results in acylation of the phosphonate by the displacement of ethoxide and the formation of (5-3). Condensation of the yhde from this intermediate with the biphenyl ester at position 11 of Corey lactone (5-4) leads to the enone (5-5) with the usual formation of a tmns olefin expected for this reaction. The very... 

T. V. RajanBabu, From carbohydrates to carbocycles. 2. A free radical route to Corey lactone and other prostanoid intermediates, J. Org. Chem. 53 4522 (1988). 

This stereochemical control in hex-5-enyl radical cyclizations can be used for the synthesis of highly functionalized cyclopentanes with vicinal trans- or cis-dialkyl-substituents. The synthesis of a versatile prostaglandin intermediate, Corey lactone 12, from the intermediate 6a (Y = OMe) has been described [14]. 

Stereoselective intermolecular photoadditions of alkenes to enones have been elegantly utilized in the synthesis of naturally occurring compounds or compounds of special interest. Sato and collaborators100 have applied the photoaddition of dioxinone 208 to the chiral r/.v-diol 207 for a one-pot synthesis of the Corey lactone 210, which possesses considerable utility in the preparation of prostaglandin derivatives (Scheme 45). 

The uses of chiral 3-carbon synthons are many and have been discussed in several reviews and other sources 18-23). Molecules that have been prepared from isopropylidene glyceraldehydes include various trialkoxynitrobutanes such as 35 and 36 24), Corey lactone variants 37 and 38 (25,26), nucleoside analogs 39-42 (27), verrucarinolactone isomers 43-46 (25), the enantiomers of roccellaric acid 47 (29), rubrenolide 48 30) and (+)-laurencin 49 (37). 

---