62210-83-7

Upstream product

• 23202-10-0 (Z)-cyclooct-2-enone 
• 84580-12-1 3a,6a-Dimethyl-1-oxo-hexahydro-cyclopenta[c]furan-4-carboxylic acid (Z)-cyclooct-2-enyl ester 
• 4925-71-7 cis-1,2-epoxycyclooctane 
• 3806-59-5 1,3-cyclooctadiene 
• 286-62-4 Cyclooctene oxide 
• 931-88-4 cis-Cyclooctene 
• 7422-06-2 (Z)-3-bromocyclooct-1-ene 

Relevant academic research and scientific papers

On the Absolute Stereochemistries of (-)-Benzocyclohepten-3-ol, (-)-2,3,4,5-Tetrahydro-1-benzoxepin-5-ol, and (-)-Benzocycloocten-3-ol

The configurations of (-)-benzocyclohepten-3-ol (2a), (-)-2,3,4,5-tetrahydro-1-benzoxepin-5-ol (6a), and (-)-benzocycloocten-3-ol (9a), which were prepared by microbial reduction of the corresponding keto compounds by Cryptococcus macerans, were established as S by conversion to dimethyl α-acetoxy dicarboxylate esters of known configuration.The elution order of the enantiomers of each of these three carbinols and their acetates from a Pirkle chiral-phase HPLC column was not consistent with that found for the lower homologues, 1-indanol and 1-tetralol.These results indicat e great care must be exercised in the use of elution order for the determination of configurations.

Guanidine–Copper Complex Catalyzed Allylic Borylation for the Enantioconvergent Synthesis of Tertiary Cyclic Allylboronates

An enantioconvergent synthesis of chiral cyclic allylboronates from racemic allylic bromides was achieved by using a guanidine–copper catalyst. The allylboronates were obtained with high γ/α regioselectivities (up to 99:1) and enantioselectivities (up to 99 % ee), and could be further transformed into diverse functionalized allylic compounds without erosion of optical purity. Experimental and DFT mechanistic studies support an SN2′ borylation process catalyzed by a monodentate guanidine–copper(I) complex that proceeds through a special direct enantioconvergent transformation mechanism.

Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols

Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely, bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton transfer/electron transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.

BIOORTHOGONAL COMPOSITIONS

The present disclosure provides bioorthogonal compositions for delivering agents in a subject. The disclosure also provides methods of producing the compositions, as well as methods of using the same.

Precision vinyl acetate/ethylene (VAE) copolymers by ROMP of acetoxy-substituted cyclic alkenes

Precision linear vinyl acetate/ethylene (VAE) copolymers containing acetoxy groups on precisely every eighth backbone carbon were synthesized by ring-opening metathesis polymerization (ROMP) of racemic 3-acetoxy cyclooctene (3AcCOE) followed by hydrogenation. The use of enantiomerically pure 3AcCOE resulted in an optically active polyalkenamer that afforded isotactic precision VAE materials after hydrogenation. Both of these VAE polymers are semicrystalline (by differential scanning calorimetry and wide-angle X-ray scattering) due to their high degrees of regioregularity and the isotactic VAE samples exhibited a higher apparent degree of crystallinity and melting point compared to the atactic version. In contrast, analogous linear VAE copolymers derived from ROMP-hydrogenation of racemic 4- or 5-acetoxy cyclooctenes were regio-irregular and completely amorphous. The ROMP-hydrogenation of 3-acetoxy cycloheptene also affords precision linear VAE copolymers with acetoxy groups on every seventh carbon, but this polymer was noncrystalline. Mechanical characterization showed that the precision 3AcCOE-derived VAE samples possess improved mechanical properties compared to the compositionally similar commercial VAE copolymers produced by radical copolymerization.

Highly selective palladium catalyzed kinetic resolution and enantioselective substitution of racemic allylic carbonates with sulfur nucleophiles: Asymmetric synthesis of allylic sulfides, allylic sulfones, and allylic alcohols

We describe the highly selective palladium catalyzed kinetic resolutions of the racemic cyclic allylic carbonates rac-1a-c and racemic acyclic allylic carbonates rac-3aa and rac-3ba through reaction with tert-butylsulfinate, tolylsulfinate, phenylsulfinate anions and 2-pyrimidinethiol by using N,N′-(1R,2R)-1,2-cyclohexanediylbis[2-(di-phenylphosphino)-benzamide] (BPA) as ligand. Selectivities are expressed in yields and ee values of recovered substrate and product and in selectivity factors S. The reaction of the cyclohexenyl carbonate 1a (≥99% ee) with 2-pyrimidinethiol in the presence of BPA was shown to exhibit, under the conditions used, an overall pseudo-zero order kinetics in regard to the allylic substrate. Also described are the highly selective palladium catalyzed asymmetric syntheses of the cyclic and acyclic allylic tert-butylsulfones 2aa, 2b, 2c, 2d and 4 a - c, respectively, and of the cyclic and acyclic allylic 2-pyrimidyl-, 2-pyridyl-, and 4-chlorophenylsulfides 5aa, 5b, 5ab, 6aa - ac, 6ba and 6bb, respectively, from the corresponding racemic carbonates and sulfinate anions and thiols, respectively, in the presence of BPA. Synthesis of the E-configured allylic sulfides 6aa, 6ab, 6ac and 6bb was accompanied by the formation of minor amounts of the corresponding Z isomers. The analogous synthesis of allylic tert-butylsulfides from allylic carbonates and tert-butylthiol by using BPA could not be achieved. Reaction of the cyclopentenyl esters rac-1da and rac-1db with 2-pyrimidinethiol gave the allylic sulfide 5c having only a low ee value. Similar results were obtained in the case of the reaction of the cyclohexenyl carbonate rac-1a and of the acyclic carbonates rac-3aa and rac-3ba with 2-pyridinethiol and lead to the formation of the sulfides 5 ab, 6 ab, and 6 bb, respectively. The low ee values may be ascribed to the operating of a "memory effect", that is, both enantiomers of the substrate give the substitution product with different enantioselectivities. However, in the reaction of the racemic carbonate rac-1 a as well as of the highly enriched enantiomers la (≥99% ee) and ent-1a (≥99% ee) with 2-pyrimidinethiol the ee values of the substrates and the substitution product remained constant until complete conversion. Similar results were obtained in the reaction of the cyclic carbonates rac-1a, ent-1a (≥99% ee) and ent-1c (≥99% ee) with lithium tert-butylsulfinate. Thus, in the case of rac-1a and 2-pyrimidinthiol and tert-butylsulfinate anion as nucleophiles the enantioselectivity of the substitution step is, under the conditions used, independent of the chirality of the substrate; this shows that no "memory effect" is operating in this case. Hydrolysis of the carbonates ent-1a-c, ent-3aa and ent-3ba, which were obtained through kinetic resolution, afforded the enantiomerically highly enriched cyclic allylic alcohols 9a-c (≥99% ee) and acyclic allylic alcohols 10a (≥99% ee) and 10b (99% ee), respectively.

Allylic alcohols via catalytic asymmetric epoxide rearrangement

Epoxides using chiral lithium amides, but other than for a small subset of meso-epoxides, insufficient reactivity and enantioselectivity hamper the existing methods. Furthermore, the chiral reagents are often required in large excess. This study presents a general and highly enantioselective process that, in addition, is based on catalytic amounts (5 mol %) of enantiopure (1S,3R,4R)-3-(1-pyrrolidinyl)methyl-2-azabicyclo[2.2.1]heptane and lithium diisopropylamide as the stoichiometric base. The influence of structural modification of the catalyst is studied in terms of activity, enantioselectivity, and aggregation behavior. The utility of the process is demonstrated by its application to a variety of epoxide derivatives (≥94% ee for 11 out of 14 examples), including the formal syntheses of, e.g., a prostaglandin core unit, epibatidine, carbovir, faranal, and lasiol. The system is readily extended to the resolution of racemic epoxides, which allows access to highly enantioenriched epoxides or allylic alcohols, even at conversions near 50%.

A novel highly effective chiral lithium amide for catalytic enantioselective deprotonation of meso-epoxides

A highly enantioselective deprotonation of meso-epoxides was achieved by a catalytic amount of a new chiral lithium amide, derived from (2S,3aS,7aS)-2-(pyrrolidin-1-ylmethyl)octahydroindole, in the presence of excess lithium diisopropylamide to afford the corresponding allylic alcohol derivatives up to 94% ee.

Catalytic enantioselective deprotonation of meso-epoxides utilising homochiral bis-lithium amide bases

(R)-2-Cyclohexen-1 ol and (R)-2-cyclooctene-1-ol have been prepared in very good ee using R,R-homochiral bis-lithium amide bases derived from homochiral C2 symmetric diamines. (R)-2-Cyclohexen-1-ol has been synthesized in good ee utilising catalytic homochiral bis-lithium amide in the presence of n-butyl lithium.

Enantioselective Synthesis of Cycloalkenols by Monohydroboration of 1,3-Cycloalkadienes with Diisocaranylboranes

Representative 1,3-cycloalkadienes were monohydroborated with di-(2-isocaranyl)borane (2-Icr2BH) and di-(4-isocaranyl)borane (4-Icr2BH) of high optical purity (>99percent ee).An efficient procedure for the oxidation of the intermediate allylic organoboranes at low temperature has been developed. 2-Cycloalkenols of moderate to high optical purity (68-96percent ee) were obtained from 2-Icr2BH and unsubstituted 6-8 membered ring dienes whereas 4-Icr2BH showed lower enantioselectivity. 1,3-Cyclopentadiene gave exclusivelly 3-cyclopentenol with both reagents.Methyl-substituted 1,3-cyclohexadienes produced corresponding 2- or 3-cyclohexenols depending on the substitution pattern of the diene. asymmetric hydroboration, conjugated cycloalkadienes, 2-cycloalkenols