The development of a childs personality is profoundly influenced by the environmental stimuli after their formation.Within this context,lullabies and childhood stories assume significant roles in this formative proces...The development of a childs personality is profoundly influenced by the environmental stimuli after their formation.Within this context,lullabies and childhood stories assume significant roles in this formative process.The familial environment serves as the primary locus from which individuals acquire their beliefs and personalities.This research investigates the portrayal of family dynamics within the narrative framework of the Persian story Smiling Flower(Gol-e Khandn).In the majority of narratives of this story,featuring the Laughing Flower,a magical agency is bestowed upon an infant girl,thereby shaping her future.The analysis of this narratives themes prioritizes the familial element,particularly the central figures of parents,who play pivotal roles in the cultivation of the childs personality.Examination of parental representation within this narrative elucidates the prominence of the maternal figure,albeit acknowledging the undeniable influence exerted by the fathers demeanor and character on the childs trajectory.展开更多
The Co_2(CO)_8-mediated intramolecular Pauson-Khand reaction is an efficient approach for constructing polycyclic skeletons. Recently, some of us reported a series of this type reactions involving stericallyhindered e...The Co_2(CO)_8-mediated intramolecular Pauson-Khand reaction is an efficient approach for constructing polycyclic skeletons. Recently, some of us reported a series of this type reactions involving stericallyhindered enynes for synthesizing natural products with reasonable reaction rates and yields. However,the reason for the high reactivity of the reaction remains unclear. We employed density functional theory calculations to clarify the mechanism and reactivity for this reaction. In contrast with chain olefin reactants, CO insertion is considered to be the rate-determining step for the overall Pauson-Khand reaction of cyclooctene derivatives. The reduced activation free energy for the alkene insertion step is attributed to: i) the electron-withdrawing group in close proximity to the C—C triple bond enhancing the reactivity of the alkyne moiety; ii) lower steric hindrance during alkene insertion when using the cyclooctene derivative. The effect of the substituent on the Co_2(CO)_8-mediated intramolecular PausonKhand reaction was then investigated. Internal alkenes exhibit lower reactivity than terminal alkenes because of the steric hindrance introduced by the substituted group. The cis internal alkene exhibits higher reactivity than the trans internal alkene. An ester group in close proximity to the C—C triple bond significantly enhances the reactivity.展开更多
The activity and enantiocontrol ability of the chiral catalysts prepared from spiro di-phosphine ligands, SDP, and rhodium precursor were investigated in the asymmetric catalytic Pau-son-Khand reaction. The results sh...The activity and enantiocontrol ability of the chiral catalysts prepared from spiro di-phosphine ligands, SDP, and rhodium precursor were investigated in the asymmetric catalytic Pau-son-Khand reaction. The results showed that SDP ligands were very effective in Rh-catalyzed Pau-son-Khand reaction, and their complexes with rhodium could convert a variety of 1,6-enyne compounds into bicyclopentone derivatives under CO atmosphere in high yields with good enantioselec-tivities. The SbF6- was found to be a suitable counter anion of the catalyst, and 1,2-dichloroethane was the best choice of the solvent for Pauson-Khand reaction.展开更多
The intermolecular Pauson-Khand reaction between 2-ethynylbenzaldehyde and ethylene promoted by dimethyl sulfide can be utilized to synthesize 2-（2-formylphenyl）cyclopentenone efficiently. This compound and its deri...The intermolecular Pauson-Khand reaction between 2-ethynylbenzaldehyde and ethylene promoted by dimethyl sulfide can be utilized to synthesize 2-（2-formylphenyl）cyclopentenone efficiently. This compound and its deriva- tives undergo a cascade process of Michael addition reaction followed by Henry reaction with nitromethane to con- struct substituted aromatic fused 2,3-dihydroindanones. Furthermore, direct one-pot synthesis of aromatic fused 2,3-dihydroindanones from 2-ethynylbenzaldehyde is achieved.展开更多
Grayanane diterpenoids,which have intricate molecular architecture and interesting pharmacological properties,have attracted considerable interest of organic chemists since 1970s.However,the total syntheses of grayana...Grayanane diterpenoids,which have intricate molecular architecture and interesting pharmacological properties,have attracted considerable interest of organic chemists since 1970s.However,the total syntheses of grayanane diterpenoids have been accomplished by only seven groups,which have mainly focused on the same carbon skeleton.Herein,we disclose the bioinspired total syntheses of six grayanane diterpenoids with three distinct carbon skeletons:grayanotoxins II/III,kalmanol,and rhodomollacetals A–C.Among them,the total syntheses of rhodomollacetals A–C were achieved for the first time.The total syntheses feature a Ni-catalyzedα-vinylation ofβ-ketoester to construct a bicyclo[3.2.1]octane ring system,an intramolecular Pauson–Khand reaction of enyne to construct a 7/5-bicyclic ring system,a biomimetic 1,2-rearrangement of grayanane-type 5/7/6/5 skeleton to generate kalmane-type 5/8/5/5 skeleton,and a biomimetic oxidative cleavage of C2–C3 and C5–C6 bonds/skeletal reconstruction to construct a rhodomollacetal A skeleton.展开更多
In this paper,we report the concise total syntheses of three botryane sesquiterpenoids:dehydrobotrydienal,dehydrobotrydienol,and 10-oxodehydrodihydrobotrydial.The key transformations include tandem Co-tetramethylthiou...In this paper,we report the concise total syntheses of three botryane sesquiterpenoids:dehydrobotrydienal,dehydrobotrydienol,and 10-oxodehydrodihydrobotrydial.The key transformations include tandem Co-tetramethylthiourea-catalyzed Pauson–Khand and 6π-electrocyclization reactions to forge the tricyclic core structure of the botryanes,and further oxidative aromatization and oxidation to complete the total syntheses.展开更多
文摘The development of a childs personality is profoundly influenced by the environmental stimuli after their formation.Within this context,lullabies and childhood stories assume significant roles in this formative process.The familial environment serves as the primary locus from which individuals acquire their beliefs and personalities.This research investigates the portrayal of family dynamics within the narrative framework of the Persian story Smiling Flower(Gol-e Khandn).In the majority of narratives of this story,featuring the Laughing Flower,a magical agency is bestowed upon an infant girl,thereby shaping her future.The analysis of this narratives themes prioritizes the familial element,particularly the central figures of parents,who play pivotal roles in the cultivation of the childs personality.Examination of parental representation within this narrative elucidates the prominence of the maternal figure,albeit acknowledging the undeniable influence exerted by the fathers demeanor and character on the childs trajectory.
基金project (Nos. 2018CDYJSY0055, 2018CDXZ0002, 106112017CDJXY220007) supported by the Fundamental Research Funds for the Central Universities (Chongqing University)supported by the National Natural Science Foundation of China (Nos. 21772020 and 21822303)
文摘The Co_2(CO)_8-mediated intramolecular Pauson-Khand reaction is an efficient approach for constructing polycyclic skeletons. Recently, some of us reported a series of this type reactions involving stericallyhindered enynes for synthesizing natural products with reasonable reaction rates and yields. However,the reason for the high reactivity of the reaction remains unclear. We employed density functional theory calculations to clarify the mechanism and reactivity for this reaction. In contrast with chain olefin reactants, CO insertion is considered to be the rate-determining step for the overall Pauson-Khand reaction of cyclooctene derivatives. The reduced activation free energy for the alkene insertion step is attributed to: i) the electron-withdrawing group in close proximity to the C—C triple bond enhancing the reactivity of the alkyne moiety; ii) lower steric hindrance during alkene insertion when using the cyclooctene derivative. The effect of the substituent on the Co_2(CO)_8-mediated intramolecular PausonKhand reaction was then investigated. Internal alkenes exhibit lower reactivity than terminal alkenes because of the steric hindrance introduced by the substituted group. The cis internal alkene exhibits higher reactivity than the trans internal alkene. An ester group in close proximity to the C—C triple bond significantly enhances the reactivity.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 20132010 and 20272026) the Major State Basic Research Development Program (Grant No. G2000077506) the Ministry of Education of China and the Committee of Science and Technology of Tianjin City for financial support.
文摘The activity and enantiocontrol ability of the chiral catalysts prepared from spiro di-phosphine ligands, SDP, and rhodium precursor were investigated in the asymmetric catalytic Pau-son-Khand reaction. The results showed that SDP ligands were very effective in Rh-catalyzed Pau-son-Khand reaction, and their complexes with rhodium could convert a variety of 1,6-enyne compounds into bicyclopentone derivatives under CO atmosphere in high yields with good enantioselec-tivities. The SbF6- was found to be a suitable counter anion of the catalyst, and 1,2-dichloroethane was the best choice of the solvent for Pauson-Khand reaction.
文摘The intermolecular Pauson-Khand reaction between 2-ethynylbenzaldehyde and ethylene promoted by dimethyl sulfide can be utilized to synthesize 2-（2-formylphenyl）cyclopentenone efficiently. This compound and its deriva- tives undergo a cascade process of Michael addition reaction followed by Henry reaction with nitromethane to con- struct substituted aromatic fused 2,3-dihydroindanones. Furthermore, direct one-pot synthesis of aromatic fused 2,3-dihydroindanones from 2-ethynylbenzaldehyde is achieved.
基金supported by the National Natural Science Foundation(grant nos.22331001 and 21925101)。
文摘Grayanane diterpenoids,which have intricate molecular architecture and interesting pharmacological properties,have attracted considerable interest of organic chemists since 1970s.However,the total syntheses of grayanane diterpenoids have been accomplished by only seven groups,which have mainly focused on the same carbon skeleton.Herein,we disclose the bioinspired total syntheses of six grayanane diterpenoids with three distinct carbon skeletons:grayanotoxins II/III,kalmanol,and rhodomollacetals A–C.Among them,the total syntheses of rhodomollacetals A–C were achieved for the first time.The total syntheses feature a Ni-catalyzedα-vinylation ofβ-ketoester to construct a bicyclo[3.2.1]octane ring system,an intramolecular Pauson–Khand reaction of enyne to construct a 7/5-bicyclic ring system,a biomimetic 1,2-rearrangement of grayanane-type 5/7/6/5 skeleton to generate kalmane-type 5/8/5/5 skeleton,and a biomimetic oxidative cleavage of C2–C3 and C5–C6 bonds/skeletal reconstruction to construct a rhodomollacetal A skeleton.
基金supported by the National Natural Science Foundation of China (Nos. 21772008, 21632002 and U1606403)Natural Science Foundation of Guangdong Province (No. 2016A030306011)+1 种基金Shenzhen Basic Research Program (Nos. JCYJ20170818090044432 and JCYJ20160226105337556)Qingdao National Laboratory for Marine Science and Technology (No. LMDBKF201703)
文摘In this paper,we report the concise total syntheses of three botryane sesquiterpenoids:dehydrobotrydienal,dehydrobotrydienol,and 10-oxodehydrodihydrobotrydial.The key transformations include tandem Co-tetramethylthiourea-catalyzed Pauson–Khand and 6π-electrocyclization reactions to forge the tricyclic core structure of the botryanes,and further oxidative aromatization and oxidation to complete the total syntheses.
