Tandem Diels−Alder Cycloadditions in Organic Synthesis

Diels-Alder cycloadditions of 2-pyrones and 2-pyridones

The article contains sections titled: 

1	Introduction	
2	Furfural	
21	Properties	
211	Physical Properties	
212	Chemical Properties	
22	Resources and Raw Materials	
23	Production	
231	Chemistry of Furfural Production	
232	Production of Furfural	
24	Uses and Economic Aspects	
25	Quality Specifications, Transportation, Toxicology	
3	Furfuryl Alcohol	
31	Properties	
311	Physical Properties	
312	Chemical Properties	
32	Resources and Raw Materials	
33	Production	
34	Uses and Economic Aspects	
35	Quality Specifications, Transportation, Toxicology	
4	Furan	
41	Properties	
42	Production	
43	Uses, Economic Aspects, Transportation, Toxicology	
5	Tetrahydrofurfuryl Alcohol	
51	Properties	
52	Production	
53	Uses, Economic Aspects, Transportation, Toxicology	
6	Furfurylamine and Tetrahydrofurfurylamine	
7	Methylfuran and Methyltetrahydrofuran	
8	Furoic acid	
 	 	
 	 	
 	 	




This article discusses the properties, production, and industrial uses of furfural and compounds derived from furfural on a commercial basis The only commercial route to furfural is acid-catalyzed digestion of pentosan sugars in biomass Nowadays, furfural is the sole precursor for all compounds containing a furyl, furfuryl, furoyl, or furfurylidene radical in the chemical industry 





Detailed information is given on the production, properties, and economical aspects of furfural [98-01-1] and furfuryl alcohol [98-00-0], and the most important specialty chemicals derived from furfural and furfuryl alcohol are summarized: furan [110-00-9], tetrahydrofurfuryl alcohol [97-99-4], 3,4-dihydro-2H-pyran [110-87-2], furfurylamine [617-89-0], tetrahydrofurfurylamine [4795-29-3], 2-methylfuran [534-22-5], 2-methyltetrahydrofuran [96-47-9], and furoic acid [88-14-2]

Furfural and Derivatives

The synthesis of carbohydrate derivatives from acyclic precursors

The first synthesis of (−)-mitrephorone A is disclosed along with discussion and study of synthetic strategies. The natural product includes a highly congested hexacyclic ent-trachylobane diterpenoid framework featuring a rare, embedded oxetane. The synthetic analysis presented dissects a number of approaches for the synthesis of the central oxetane, including carbonyl-olefin photocycloadditions, Prins-type cyclizations, and oxidative ring closures. In the successful route, three [4 + 2] cycloadditions enable rapid construction of all carbocycles. A novel late-stage oxidative cyclization of a hydroxy diosphenol with Koser’s reagent furnishes the pivotal oxetane moiety.

Total Synthesis of (−)-Mitrephorone A

Thermal reaction of coumalic acid with 1,3-butadienes gave after diazomethane treatment dimethyl tricyclo[32102,7]oct-3-ene-2,4-dicarboxylate via double Diels-Alder reaction This represents the simplest synthesis of such a tricyclic system The reaction with cyclopentadiene was also studied

Double Diels-Alder reactions of coumalic acid with 1,3-dienes.

The reaction of furfuryl alcohols with maleic anhydride leads to tricyclic lactone-carboxylic acids through the sequence of esterification and intramolecular Diels–Alder reaction. Anodic oxidative decarboxylation of the hydrogenated products in MeOH affords 1,2,3-trisubstituted cyclopentane derivatives, viz. 1-hydroxymethyl-3-methoxy-2-oxabicyclo[2.2.1]heptane-7-syn-carboxylic lactones, potential intermediates for synthesis of iridoids.

A synthetic method for novel 1,2,3-trisubstituted cyclopentane derivatives, 1-hydroxymethyl-3-methoxy-2-oxabicyclo(2.2.1)heptane-7-carboxylic lactones.

A synthetic method for novel 1,2,3-trisubstituted cyclopentane derivatives, 1-(hydroxymethyl)-3-methoxy-2-oxabicyclo(2.2.1)heptane-7-carboxylic lactones

Thermal reaction of coumalic acid with 1,3-butadienes gave after diazomethane treatment dimethyl tricyclo[3.2.1.02,7]oct-3-ene-2,4-dicarboxylate via double Diels-Alder reaction. This represents the simplest synthesis of such a tricyclic system. The reaction with cyclopentadiene was also studied.

T. Nakagawa

Papers

Double Diels-Alder reactions of coumalic acid with 1,3-dienes.

A synthetic method for novel 1,2,3-trisubstituted cyclopentane derivatives, 1-hydroxymethyl-3-methoxy-2-oxabicyclo(2.2.1)heptane-7-carboxylic lactones.

A synthetic method for novel 1,2,3-trisubstituted cyclopentane derivatives, 1-(hydroxymethyl)-3-methoxy-2-oxabicyclo(2.2.1)heptane-7-carboxylic lactones

Double diels-alder reactions of coumalic acid with 1,3-dienes