89241-26-9Relevant academic research and scientific papers
Fused N-Heterocycles with Contiguous Stereogenic Centers Accessed by an Asymmetric Catalytic Cascade Reaction of Tertiary Enamides
Zhen, Li,Tong, Shuo,Zhu, Jieping,Wang, Mei-Xiang
supporting information, p. 401 - 405 (2019/12/24)
We report in this article a cascade reaction strategy for the synthesis of complex N-heterocyclic compounds with contiguous and tetrasubstituted stereogenic carbons. Under the sequential catalysis of a chiral binol–Ti complex and BF3, cyclopentanone-derived tertiary enamides undergo an enantioselective enamine addition to ketone carbonyls followed by diastereoselective trapping of the resulting acyliminiums by electron-rich aryl moieties to furnish four- and five-membered ring-fused N-heterocyclic products as the sole diastereomers in high yields with up to 99 % ee.
Intramolecular Acylal Cyclisation (IAC) as an Efficient Synthetic Strategy towards the Total Synthesis of Erythrina Alkaloid Derivatives
Monaco, Alessandra,Aliev, Abil E.,Hilton, Stephen T.
supporting information, p. 13909 - 13912 (2015/09/28)
Compounds that comprise the erythrina alkaloid class of natural products are based on a tetracyclic spiroamine framework and exhibit a range of biological activities on the central nervous system. Herein, we report a new and efficient total synthesis of this multiple-ring system based on an intramolecular acylal cyclisation (IAC) approach. Using this methodology, the tetracyclic core was rapidly assembled over a two-step domino process catalysed by a Lewis acid. The effect of heteroatoms, substituents and ring size on the IAC has also been investigated, and the broad application of this procedure is demonstrated by the synthesis of a library of derivatives in good yields with excellent regioselectivity. Extending the diversity of the erythrina core: The tetracyclic core of the erythrina alkaloid family can be accessed through a Lewis acid mediated intramolecular acylal cyclisation (IAC) approach in two steps. Using this, heteroatoms and variation of the cyclohexyl ring produced a library of derivatives in good yields and with excellent regioselectivity.
A convenient synthesis of 1,1-disubstituted 1,2,3,4-tetrahydroisoquinolines via Pictet-Spengler reaction using titanium(IV) isopropoxide and acetic-formic anhydride.
Horiguchi, Yoshie,Kodama, Hirokazu,Nakamura, Masayoshi,Yoshimura, Tsuyoshi,Hanezi, Kaori,Hamada, Hiroko,Saitoh, Toshiaki,Sano, Takehiro
, p. 253 - 257 (2007/10/03)
A synthesis of 1,1-disubstituted 1,2,3,4-tetrahydroisoquinolines (6) was achieved in a highly efficient manner via Pictet-Spengler reaction of arylethylamines (1) and acyclic and cyclic ketones (2) using titanium (IV) isopropoxide and acetic-formic anhydride. The cyclization of the in situ formed acyliminium ion (4) to N-formyl 1,2,3,4-tetrahydroisoquinoline (5) was greatly facilitated by using trifluoroacetic acid as an additional reagent. The Pictet-Spengler reaction was carried out by one pot procedure, providing a convenient and effective method for preparing various 1,2,3,4-tetrahydroisoquinolines.
THE PHOTOCHEMICAL OR THERMAL REARRANGEMENT OF OXAZIRANES AS A METHOD IN ALKALOID SYNTHESIS
Kuehne, Martin E.,Parsons, W. H.
, p. 3763 - 3766 (2007/10/02)
The conversion of cyclic ketones to β-arylethyl amine derived imines, their oxidation to oxaziranes and subsequent photochemical rearrangement to N-(β-arylethyl) lactams was probed as a potential method for alkaloid syntheses.
