95530-78-2

Upstream product

• 134297-24-8 (1R,2R,4R)-(+)-oxabicyclo<2.2.1>hept-5-ene-2-p-tolyl sulfide 
• 79902-01-5 2-endo-acetoxy-7-oxabicyclo<2.2.1>hept-5-ene-2-exo-carbonitrile 
• 134297-23-7 (1R,4R,5R)-5-((R)-Toluene-4-sulfinyl)-7-oxa-bicyclo[2.2.1]hept-2-ene 
• 120056-66-8 (1RS,4RS)-2-cyano-7-oxabicyclo<2.2.1>hept-5-ene-2-yl acetate 

Downstream Products

• 107607-60-3 (1S,2S,6S,7S)-5-Phenyl-3,10-dioxa-4-aza-tricyclo[5.2.1.0^2,6]dec-4-en-9-one 
• 107607-59-0 (1S,2R,6R,7S)-5-Phenyl-3,10-dioxa-4-aza-tricyclo[5.2.1.0^2,6]dec-4-en-8-one 
• 105183-24-2 (+/-)-(1RS,4SR,5SR,6SR)-6-endo-chloro-5-exo-(phenylseleno)-7-oxabicyclo[2.2.1]heptan-2-one 
• 115140-08-4 (1RS,2RS)-5,5-bis(benzyloxy)-7-oxabicyclo<2.2.1>hept-2-ene 
• 105205-34-3 (1S,4R,5R,6R)-5-Benzenesulfonyl-6-phenylselanyl-7-oxa-bicyclo[2.2.1]heptan-2-one 
• 114744-47-7 2-exo-phenyl-7-oxabicyclo<2.2.1.>hept-5-en-2-endo-ol 
• 2745-26-8 furan-2-yl-acetic acid 
• 58564-88-8 7-oxa-bicyclo[2.2.1]heptan-2-one 
• 120-80-9 benzene-1,2-diol 
• 105183-25-3 6-endo-chloro-5-exo-(2-nitrobenzenesulfenyl)-7-oxabicyclo<2.2.1>heptan-2-one 
• 114744-47-7 2-endo-phenyl-7-oxabicyclo<2.2.1>hept-5-en-2-exo-ol 
• 123075-89-8 (1R,2R,6R,7R)-5-(2,4,6-Trimethyl-phenyl)-3,10-dioxa-4-aza-tricyclo[5.2.1.0^2,6]dec-4-en-9-one 
• 123075-85-4 (1S,2R,6R,7S)-5-(2,4,6-Trimethyl-phenyl)-3,10-dioxa-4-aza-tricyclo[5.2.1.0^2,6]dec-4-en-8-one 
• 114765-67-2 5-exo-methyl-2-exo-phenylsulfenyl-4,7-dioxatricyclo<3.2.1.0^3,6>octane 

Relevant academic research and scientific papers

Synthesis of 2,6-dioxabicyclo[3.3.0]octenes by tandem ring-rearrangement/cross metathesis

A facile synthesis of stereodefined 2,6-dioxabicyclo[3.3.0]octene derivatives from the vinyl ether of endo-7-oxanorbornen-2-ol via tandem ring-opening/ring-closing(ring-rearrangement)/cross metathesis is reported.

(1R,3R)-2-Methylene-1,3-dithiolane 1,3-dioxide: A highly reactive and highly selective chiral ketene equivalent in cycloaddition reactions with a broad range of dienes

The chiral ketene equivalent trans-2-methylene-1,3-dithiolane 1,3-dioxide has been prepared in racemic and enantiomerically pure form in four steps. The key step in the asymmetric synthesis utilised a Modena asymmetric oxidation of 2-benzyloxymethyl-1,3-dithiolane which gave the trans bis-sulfoxide with high diastereocontrol (91:9 in favour of trans) and high enantiocontrol (>97% ee). The ketene equivalent shows high selectivity (>97:3) in Diels-Alder reactions with a range of simple dienes (cyclopentadiene, furan, 1-methoxybutadiene, Danishefsky's diene, 1-methoxycyclohexa-1,3-diene) and shows high reactivity as it is able to undergo cycloadditions with notoriously unreactive dienes (cyclohexa-1,3-diene, 90:10 selectivity; 2H-pyran-2-one, 94:6 selectivity). Dihydropyridines also participated in cycloaddition reaction but with only moderate selectivity (73:27). The Diels-Alder adducts can be readily deprotected to return the carbonyl group using a two step sequence involving reduction followed by hydrolysis.

DEVELOPMENT OF METHODOLOGY BASED ON THE USE OF THE 7-OXABICYCLOHEPTANYL SYSTEM FOR THE PREPARATION OF CARBOHYDRATE DERIVATIVES

The 7-oxabicycloheptanyl system provides a rapid entry to carbohydrate derivatives in a stereoselective manner by virtue of the rigid framework.The formation of this bicyclic system through a Diels-Alder reaction of furan with a number of dienophil

Homochiral Matching in the Diels-Alder Cyclodimerization of 2-Vinyl-7-oxabicyclohept-2-ene Derivatives.

Keywords: Face selectivity, -cycloadditions, chiral recognition, (1R,2S,3S,4R,7R,11S,12R)-11-ethenyl-15,16-dioxapentacyclo4,7.03,8.02,11>hexadec-8-en-6,13-dione, (1R,2R,3R,4R,7R,11R,12R)-11-ethenyl-15,16-dioxapentacyclo4,7.03,8.02,11>hexadec-8-en-5,14-dione and their ethylene acetals.Abstract: Racemic 6-vinyl-7-oxabicyclohept-5-en-2-one, 5-vinyl-7-oxabicyclohept-5-en-2-one and their ethylene acetals undergo highly stereoselective Diels-Alder cyclodimerizations.The optically pure semicyclic dienes give the corresponding optically pure dimers with the same ease.

Highly diastereoselective Diels-Alder reactions with (R)-ethoxy p-tolyl vinyl sulfonium tetrafluoroborate

p-Tolyl vinyl sulfoxide has been efficiently activated for the Diles-Alder reactions by transformation into a sulfonium salt 3a or by addition of TMSOTf.Very high diastereomeric excesses have been achieved (>98percent) at -20 deg C in many cases.Best results have been obtained with cyclopentadiene, furan and 2,3-dimethyl-1,3-butadiene.In this way enantiomerically pure oxanorbornenone 19a has been prepared.The reaction mechanism is briefly discussed.

Norbornanes. Part 21. Bridging Strain in Norbornyl and Oxanorbornyl Cations

Further evidence is presented that the 2-norbonyl cation is stabilized primarily by C(2)-C(6) bridging, and that C(2)-C(7) bridging leads to prohibitive strain.Thus, a comparison of the heats of hydrogenation of nortricyclene 17 and bicyclo2,7>heptane 18 indicates that the strain energy of the latter is ca. 21.5 kcal/mol higher than that of 17.Furthermore, 6-exo-2-oxabicycloheptyl sulfonates 8 ionize with strong O(2) participation to the bridged oxonium ion 12.In contrast, 2-endo-7-oxabicycloheptyl sulfonates 11 ionize without O(7) participation to form the unbridged carbenium ion 15.

SYNTHESIS OF (+)- AND (-)-METHYL 8-EPINONACTATE AND (+)- AND (-)-METHYL NONACTATE

n four synthetic steps, (+)- and (-)-methyl 8-epinonactate ((+)- and (-)-4) have been derived from (+)- and (-)-7-oxabicycloheptan-2-one ((+)- and (-)-9), respectively.The (+)- and (-)-maethyl nonactate ((+)- and (-)-3) were obtained from (+)- and (-)-4, respectively, by Mitsunobu displacement reactions.Optical resolution of (+/-)-9 via cromatographic separation of the corresponding N-methyl-S-alkyl-S-phenylsulfoximides 24 and 25 yielded the starting material (+)- and (-)-9, respectively.

Optical Resolution of 7-Oxabicyclohept-2-ene Derivatives. Diastereoselectivity in the Formation of Cyanohydrine-Brucine Complexes

A new, practical method for the optical resolution of bicyclic ketones is illustrated by the preparation of (+)-(1R,4R)-7-oxabicyclohept-5-en-2-one ((+)-1) and (+)-(1R,2S,4R)-2-cyano-7-oxabicyclohept-5-en-2-yl acetate ((+)-4).It involves the diastereoselective formation of a brucine complex with the corresponding cyanhydrine mixture.

Synthesis of Precursors of C4 and C5 Cumulenones

Bicyclohept-5-en-2-one was condensed with 2,2-dimethyl-1,3-dioxan-4,6-dione in the presence of titanium tetrachloride/pyridine to yield 5-(bicyclohept-5'-en-2'-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione (6a) which on pyrolysis at 520-560 deg/0.01 mm gave acetone, carbon dioxide, cyclopentadiene and butatrienone.In the same way 5-(7'-oxabicyclohept-5'-en-2'-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione (6b) was prepared from 7-oxabicyclohept-5-en-2-one and on pyrolysis at 570 deg/0.01 mm it gave acetone, carbon dioxide, furan and butatrienone.Alkylation of 2-trimethylsiloxybicyclohepta-2,5-diene with phenylthiomethyl chloride with titanium tetrachloride as catalyst followed by condensation with 2,2-dimethyl-1,3-dioxan-4,6-dione gave an endo/exo mixture of 5-(3'-phenylthiomethylbicyclohept-5'-en-2'-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione.The structure of the endo isomer was established by X-ray crystallography.Oxidation of the phenylthiomethyl compound with m-chloroperbenzoic acid yielded the sulfoxide which was converted by boiling in carbon tetrachloride into 5-(3'-methylenebicyclohept-5'-en-2'-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione (8).Preliminary studies on the fragmentation of compound (8) have shown that at 450 deg/0.01 mm it is converted into acetone, carbon dioxide and products showing ketene absorption at 2140 cm-1.The formation of pentatetraenone has not been established with certainty.The 3'-phenylsulfonylmethyl, phenylselenyl and methyl derivatives of (6a) are also described.