459174-16-4Relevant academic research and scientific papers
Hydrodealkenylative C(sp3)–C(sp2) bond fragmentation
Smaligo, Andrew J.,Swain, Manisha,Quintana, Jason C.,Tan, Mikayla F.,Kim, Danielle A.,Kwon, Ohyun
, p. 681 - 685 (2019/06/11)
Chemical synthesis typically relies on reactions that generate complexity through elaboration of simple starting materials. Less common are deconstructive strategies toward complexity—particularly those involving carbon-carbon bond scission. Here, we introduce one such transformation: the hydrodealkenylative cleavage of C(sp3)–C(sp2) bonds, conducted below room temperature, using ozone, an iron salt, and a hydrogen atom donor. These reactions are performed in nonanhydrous solvents and open to the air; reach completion within 30 minutes; and deliver their products in high yields, even on decagram scales. We have used this broadly functionality tolerant transformation to produce desirable synthetic intermediates, many of which are optically active, from abundantly available terpenes and terpenoid-derived precursors. We have also applied it in the formal total syntheses of complex molecules.
Fate of diradicals in the caldera: Stereochemistry of thermal stereomutation and ring enlargement in cis- and trans-1-cyano-2(E)- propenylcyclopropanes
Doering, William Von E.,Barsa, Edward Albert
, p. 12353 - 12362 (2007/10/03)
This study of thermally induced stereomutation and ring enlargement in both (-)-trans-1-cyano-2(E)-propenylcyclopropane [(-)-trans-1] and (+)-cis-1-cyano-2(E)-propenylcyclopropane [(+)-cis-1] to cyclopentenes definitively contraindicates the usefulness of Woodward-Hoffmann rules of orbital symmetry as a theoretical basis for predicting the stereochemistry of the products. From both diastereomers, the same (+)-trans-4-cyano-3- methylcyclopentene [(+)-trans-2] is the major product among the four diastereomeric products, "allowed" and formally the result of a single internal rotation of the cyano-bearing carbon atom from (-)-trans-1, "forbidden" and the result of zero internal rotations from (+)-cis-1. Stereomutation and ring enlargement are discussed in detail in terms of rotational propensity, thermodynamic preference, and the possible role of diradicals in transit and diradicals as intermediates in a caldera.
Asymmetric synthesis of 1,2,3-trisubstituted cyclopentanes and cyclohexanes as key components of substance P antagonists
Kuethe, Jeffrey T.,Wong, Audrey,Wu, Jimmy,Davies, Ian W.,Dormer, Peter G.,Welch, Christopher J.,Hillier, Michael C.,Hughes, David L.,Reider, Paul J.
, p. 5993 - 6000 (2007/10/03)
An efficient asymmetric synthesis of 1,2,3-trisubstituted cyclopentanes and cyclohexanes is described. Three methods were developed for the preparation of the 2,3-disubstituted cyclopentenones and cyclohexenones, which are key achiral building blocks. These intermediates are reduced catalytically with (R)-2-methyloxazaborolidine in high yield (82-98%) and excellent ee (89-96%). Directed reduction of the chiral allylic alcohols using Red-Al gives exclusively the 1,2-anti stereochemistry (>99:1). Epimerization of the ester center followed by saponification/crystallization affords the desired hydroxyacids in good yield (65-70%) and in high enantiomeric excess (>99%).
Regiochemical control of the ring opening of 1,2-epoxides by means of chelating processes. 9. Synthesis and ring opening reactions of cis- and trans-oxides derived from 3-(benzyloxymethyl)cyclopentene and methyl 2- cyclopenten-1-carboxylate
Colombini,Crotti,Di Bussolo,Favero,Gardelli,Macchia,Pineschi
, p. 8089 - 8112 (2007/10/02)
The regiochemical outcome of the ring opening of 1,2-epoxides through chelation processes assisted by metal ions, was verified in the oxirane systems derived from cyclopentene bearing a polar functionality (CH2OBn or COOMe) in a homoallylic relationship to the oxirane ring. The cis/trans diastereoisomeric epoxide pairs 7-8 and 9-10 derived from 3- (benzyloxymethyl)cyclopentene and methyl 2-cyclopenten-1-carboxylate, respectively, were prepared and some of their opening reactions were studied. The regioselectivity observed turned out to depend on the opening reaction protocol (standard or metal-assisted), suggesting the efficacious incursion, under the appropriate conditions, of chelate bidentate species in the opening process.
Synthesis of Carbocyclic Systems via Radical-Induced Epoxide Fragmentation
Rawal, Viresh H.,Newton, Randall C.,Krishnamurthy, Venkat
, p. 5181 - 5183 (2007/10/02)
Cis-fused bicyclic compounds are synthesized from simple monocyclic enone precursors.The key step involves a tandem radical-mediated epoxide fragmentation, radical translocation, and cyclization.
