52203-23-3Relevant academic research and scientific papers
Amide Effects in C?H Activation: Noncovalent Interactions with L-Shaped Ligand for meta Borylation of Aromatic Amides
Bisht, Ranjana,Hoque, Md Emdadul,Chattopadhyay, Buddhadeb
supporting information, p. 15762 - 15766 (2018/11/10)
A new concept for the meta-selective borylation of aromatic amides is described. It has been demonstrated that while esters gave para borylations, amides lead to meta borylations. For achieving high meta selectivity, an L-shaped bifunctional ligand has been employed and engages in an O???K noncovalent interaction with the oxygen atom of the moderately distorted amide carbonyl group. This interaction provides exceptional control for meta C?H activation/borylation.
Concise enantioselective total syntheses of (+)-homochelidonine, (+)-chelamidine, (+)-chelidonine, (+)-chelamine and (+)-norchelidonine by a PdII-catalyzed ring-opening strategy
Fleming, Matthew J.,McManus, Helen A.,Rudolph, Alena,Chan, Walter H.,Ruiz, Jeremy,Dockendorff, Chris,Lautens, Mark
experimental part, p. 2112 - 2124 (2009/04/06)
New enantioselective syntheses of the B/C hexahydrobenzo[c]phenanthridine alkaloids (+)-homochelidonine, (+)-chelamidine, (+)-chelidonine, (+)-chelamine, and (+)-norchelidonine are described. Our rapid and convergent route to this class of natural products involved the development and application of a Pd II-catalyzed asymmetric ring-opening reaction of a mesoazabicyclic alkene with an aryl boronic acid as the key step. By screening a variety of functionalized ortho-substituted aryl boronic acids, chiral ligands and reaction conditions we were able to prepare the requisite cis-1-amino-2- aryldihydronaphthalenes in high yield and in up to 90% ee. Early attempts to complete the synthesis of (+)-homochelidonine using an N-Boc azabicyclic alkene are described in full. The successful route required a protecting group alteration followed by B ring for-mation and then stereoselective installation of the C-11 syn-hydroxy group by regioselective epoxide ring-opening using a hydride source. Ring-opening of the same epoxide intermediate with water ultimately led to the synthesis of (+)-chelamidine. The same strategy was then used to synthesize the other structurally similar B/C hexahydrobenzo[c] phenanthridine alkaloids, (+)-chelidonine, (+)-chelamidine, and (+)norchelidonine.
Directed Ortho Metalations of Tertiary Benzamides Using Lactones as Electrophiles
Brenstrum, Timothy J.,Brimble, Margaret A.,Stevenson, Ralph J.
, p. 4897 - 4904 (2007/10/02)
Directed ortho metalation of oxygenated tertiary benzamides using tert-butyllithium in THF/TMEDA at -78 deg C followed by the addition of a range of lactones afforded ortho-substituted keto-alcohols in good yield.
