17015-63-3Relevant academic research and scientific papers
Combining Palladium and Chiral Organocatalysis for the Enantioselective Deconjugative Allylation of Enals via Dienamine Intermediates
Hu, Guang,Brenner-Moyer, Stacey E.
, p. 866 - 873 (2022/01/04)
A catalytic enantioselective deconjugative allylation of enals is reported. A variety of enals underwent this transformation in high yield and ee, and products can be readily transformed into γ-allyl enals via a Cope rearrangement without erosion of ee. This transformation was used to install the quaternary stereocenter in (S)-bakuchiol, enabling completion of a concise formal synthesis.
Regioselective molybdenum-catalyzed allylic substitution of tertiary allylic electrophiles: Methodology development and applications
Khan, Ajmal,Khan, Shahid,Salman, Muhammad,Xu, Yaoyao,Zhang, Junjie
, p. 5481 - 5486 (2020/06/10)
The first molybdenum-catalyzed allylic sulfonylation of tertiary allylic electrophiles is described. The method employs a readily accessible catalyst (Mo(CO)6/2,2′-bipyridine, both are commercially available) and represents the first example of the use of a group 6 transition metal-catalyst for allylic sulfonylation of substituted tertiary allylic electrophiles to form carbon-sulfur bonds. This atom economic and operationally simple methodology is characterized by its relatively mild conditions, wide substrate scope, and excellent regioselectivity profile, thus unlocking a new platform to forge sulfone moieties, even in the context of late-stage functionalization and providing ample opportunities for further derivatization through traditional Suzuki cross-coupling reactions.
Synthesis of Chiral Tertiary Boronic Esters: Phosphonate-Directed Catalytic Asymmetric Hydroboration of Trisubstituted Alkenes
Chakrabarty, Suman,Takacs, James M.
, p. 6066 - 6069 (2017/05/09)
Highly enantioselective rhodium-catalyzed hydroboration of allylic phosphonates by pinacolborane affords chiral tertiary boronic esters. The β-borylated phosphonates are readily converted to chiral β- and γ-hydroxyphosphonates and aminophosphonates and to phosphonates bearing a quaternary carbon stereocenter. The utility of the latter is illustrated by the synthesis of (S)-(+)-bakuchiol methyl ether.
Anti-proliferative evaluation of monoterpene derivatives against leukemia
Gautam, Lekh Nath,Ling, Taotao,Lang, Walter,Rivas, Fatima
supporting information, p. 75 - 80 (2016/03/01)
The cure rate of pediatric acute lymphoblastic leukemia (ALL) has significantly improved in the past thirty years, however not all patient cohorts respond well to current chemotherapy regimens. Among the high risk patient cohort is infants with MLL-rearranged (MLL-r) B-ALL, which remains dismal with an overall survival rate 35%. Our program is interested in identifying new molecular scaffolds to better understand the underlying mechanisms and ultimately provide new targeted treatments. Based on a phenotypic screen, phenolic natural products were identified as promising scaffolds for further chemical evaluation. Herein we disclose the effects of a potent anti-proliferative compound 31 against human ALL leukemia cellular models.
Enantioselective Synthesis of Quaternary Stereocenters via Chromium Catalysis
Xiong, Yang,Zhang, Guozhu
supporting information, p. 5094 - 5097 (2016/10/14)
Asymmetric allylation of aldehydes with γ-disubstituted allyl halides has been achieved in the presence of a sulfonamide/oxazoline chromium complex. A variety of synthetically useful α-homoallylic alcohols with two consecutive stereogenic centers, including one quaternary carbon, can be accessed in a highly diastereoselective and enantioselective manner.
A short synthesis of (+)-bakuchiol
Esumi, Tomoyuki,Yamamoto, Chihiro,Fukuyama, Yoshiyasu
, p. 1845 - 1847 (2013/09/12)
The concise enantioselective total synthesis of (+)-bakuchiol has been achieved using an asymmetric 1,4-addition to construct its all-carbon chiral quaternary center based on the induction of chirality by the (2′S)-2′-phenyloxazolidinone auxiliary, followed by a one-pot transformation under aldol reaction conditions. The synthesis was completed in four steps from (E)-geranic acid in an overall yield of 53%. Georg Thieme Verlag Stuttgart · New York.
A facile asymmetric synthesis of Δ3-2-Hydroxybakuchiol, Bakuchiol and ent-Bakuchiol
Xu, Qian-Qian,Zhao, Qun,Shan, Guang-Sheng,Yang, Xi-Cheng,Shi, Qi-Yuan,Lei, Xinsheng
, p. 10739 - 10746 (2013/12/04)
A facile asymmetric synthesis of Δ3-2-Hydroxybakuchiol, Bakuchiol, and ent-Bakuchiol is described through one common intermediate bearing a chiral all-carbon quaternary carbon center, which involves stereoselectively unconjugated alkylation of the α,β-unsaturated imide bearing Evans' auxiliary, Takai-Utimoto reaction, Negishi reaction, and Heck reaction as key steps.
Bakuchiol derivatives as novel and potent cytotoxic agents: A report
Majeed, Rabiya,Reddy, Mallepally V.,Chinthakindi, Praveen K.,Sangwan, Payare L.,Hamid, Abid,Chashoo, Gousia,Saxena, Ajit K.,Koul, Surrinder
experimental part, p. 55 - 67 (2012/04/10)
A library of 28 compounds comprising of acyl, amino, halo, nitro, styryl and cyclized derivatives of bakuchiol have been evaluated against a panel of eight human cancer cell lines. Bioevaluation studies have resulted in the identification of potent cytoto
Asymmetric construction of all-carbon quaternary stereocenters by chiral-auxiliary-mediated claisen rearrangement and total synthesis of (+)-Bakuchiol
Takao, Ken-Ichi,Shu, Sakamoto,Touati, Marianne Ayaka,Kusakawa, Yusuke,Tadano, Kin-Ichi
, p. 13330 - 13344 (2013/02/23)
An asymmetric Claisen rearrangement using Oppolzer's camphorsultam was developed. Under thermal conditions, a geraniol-derived substrate underwent the rearrangement with good stereoselectivity. The absolute configuration of the newly formed all-carbon quaternary stereocenter was confirmed by the total synthesis of (+)-bakuchiol from the rearrangement product.
Synthesis of quaternary carbon stereogenic centers through enantioselective Cu-catalyzed allylic substitutions with vinylaluminum reagents
Gao, Fang,McGrath, Kevin P.,Lee, Yunmi,Hoveyda, Amir H.
supporting information; experimental part, p. 14315 - 14320 (2010/12/19)
Catalytic enantioselective allylic substitution (EAS) reactions, which involve the use of alkyl- or aryl-substituted vinylaluminum reagents and afford 1,4-dienes containing a quaternary carbon stereogenic center at their C-3 site, are disclosed. The C-C bond-forming transformations are promoted by 0.5-2.5 mol % of sulfonate bearing chiral bidentate N-heterocyclic carbene (NHC) complexes, furnishing the desired products efficiently (66-97% yield of isolated products) and in high site (>98% SN2′)- and enantioselectivity [up to 99:1 enantiomer ratio (er)]. To the best of our knowledge, the present report puts forward the first cases of allylic substitution reactions that result in the generation of all-carbon quaternary stereogenic centers through the addition of a vinyl unit. The aryl- and vinyl-substituted vinylaluminum reagents, which cannot be prepared in high efficiency through direct reaction with diisobutylaluminum hydride, are accessed through a recently introduced Ni-catalyzed reaction of the corresponding terminal alkynes with the same inexpensive metal-hydride agent. Sequential Ni-catalyzed hydrometalations and Cu-catalyzed C-C bond-forming reactions allow for efficient and selective synthesis of a range of enantiomerically enriched EAS products, which cannot be accessed by previously disclosed strategies (due to inefficient vinylmetal synthesis or low reactivity and/or selectivity with Si-substituted derivatives). The utility of the protocols developed is demonstrated through a concise enantioselective synthesis of natural product bakuchiol.
