Reaction Of Vinylcarbenoids Research Articles

ChemInform Abstract: Reaction of Vinylcarbenoids with Aldehydes: Formation of Vinylcarbonyl Ylides Followed by Ring Closure to Oxiranes and Dihydrofurans.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Reaction of Vinylcarbenoids with Benzaldehydes: Formation of Vinylcarbonyl Ylides Followed by Ring Closure to Oxiranes and Dihydrofurans.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reaction of vinylcarbenoids with benzaldehydes: formation of vinylcarbonyl ylides followed by ring closure to oxiranes and dihydrofurans.

Rh(2)(OAc)(4)-catalyzed reaction of vinyldiazo compound 1a in the presence of p-methoxybenz- 2a, mesit- 2b, and p-chlorobenzaldehyde 2c gave a mixture of isomeric vinyloxiranes 3a-c and 4a-c, and sterically unstable (E)-dihydrofurans 5a-c, but not stable (Z)-dihydrofurans 6. However, the reactions with p-nitro- 2d and 2,4-dinitrobenzaldehyde 2e gave (Z)-dihydrofurans 6d,e along with 3d, 4d, and 5d,e. The reaction in the presence of maleic anhydride and dimethyl fumarate gave single 1,3-dipolar cycloadducts 11 and 13, respectively, indicating that a single conformer, the sterically unstable endo-aryl-endo-cyanostyryl carbonyl ylide 14 (15), is initially formed in the reaction of 1 with 2. It was concluded that the endo-vinyl-exo-aryl vinylcarbonyl ylides 17a-c arising from 2a-c undergo disrotatory cylization to exclusively produce 5, whereas the ylides 17d,e arising from 2d,e undergo partly symmetry-forbidden conrotaory cyclization to sterically stable trans-diaryldihydrofurans 6d,e as well as the symmetry-allowed process to 5d,e.

ChemInform Abstract: Reaction of Vinylcarbenoids with Thioketones: Formation of Vinylthiocarbonyl Ylides Followed by Ring Closure to Thiiranes and Dihydrothiophenes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reaction of vinylcarbenoids with aldehydes: formation of vinylcarbonyl ylides followed by ring closure to oxiranes and dihydrofurans

Rh 2(OAc) 4-catalyzed reaction of vinyldiazo compound 1 in the presence of benzaldehydes 2a– 2c gave a mixture of isomeric vinyloxiranes 3 and 4, and sterically unstable ( E)-dihydrofurans 5, but not stable ( Z)-dihydrofurans 6. However, the reaction in the presence of maleic anhydride gave single 1,3-dipolar cycloadducts 15, indicating that onyl endo-aryl- endo-cyanostyryl carbonyl ylide 7 ( 8) is initially formed in the reaction of 1 with 2.

Reaction of vinylcarbenoids with thioketones: formation of vinylthiocarbonyl ylides followed by ring closure to thiiranes and dihydrothiophenes

Reactions were carried out on thioketones with vinylcarbenoids. Rh 2(OAc) 4-catalyzed reaction of vinyldiazo compounds 1a,b with xanthione 2 and thiochromone 3 gave thiiranes 4b and olefins 5 and 6, desulfurization products from thiiranes, while the reaction of 1c with 2 and 3 afforded dihydrothiophenes 7, 8 and 9.

ChemInform Abstract: Reaction of Vinylcarbenoids with Cyclic Disulfides: Formation of 1,3‐Insertion Products as well as 1,1‐Insertion Products.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reaction of vinylcarbenoids with cyclic disulfides: Formation of 1,3-insertion products as well as 1,1-insertion products

Reactions of vinylcarbenoids with cyclic disulfides were carried out. Rh 2(OAc) 4-catalyzed reaction of vinyldiazo compounds 1a-c with biphenylene disulfide 6 gave 1,3-insertion adducts 7a-c as the sole products in very good yields, while the reaction with dithiaphenanthrene 9 afforded only 1,1-insertion adducts 10a-c.

Carbenoid versus Vinylogous Reactivity in Rhodium(II)-Stabilized Vinylcarbenoids

Rhodium(II)-stabilized vinylcarbenoid intermediates display electrophilic character at both the carbenoid site and the vinylogous position. The solvent and catalyst as well as the vinylcarbenoid structure have major effects on the regiochemical outcome of the reaction of vinylcarbenoids with alkenes and dienes. Reaction of vinylcarbenoids with vinyl ethers can lead to the formation of either cyclopropanes or cyclopentenes while reaction of vinylcarbenoids with cyclopentadiene can lead to the formation of either bicyclo[3.2.1]octadiene or bicyclo[2.2. 1]heptene derivatives