Iridium-catalyzed hydroacylation reactions of C1-substituted oxabenzonorbornadienes with salicylaldehyde: an experimental and computational study

• Angel Ho,
• Austin Pounder,
• Krish Valluru,
• Leanne D. Chen and
• William Tam

Beilstein J. Org. Chem. 2022, 18, 251–261, doi:10.3762/bjoc.18.30

• , the regioselectivity of such reactions is still undefined (Scheme 1) [58]. While the chemistry of symmetric OBD derivatives is well established, their unsymmetrically substituted counterparts 5 have remained underexplored (Scheme 1). Upon C1-substitution, the reactivity of C1-substituted OBDs 5 can

• can be formed based on a complex relationship between the reactants, C1-substituent, and reaction conditions [58]; therefore, it is paramount to understand of the effects that C1-substitution has on the reactions. Inspired by the initial work of Nishimura and co-workers [64], we pursued a study on the

• effects of C1-substitution on the iridium-catalyzed hydroacylation reactions of unsymmetrical OBDs with salicylaldehyde. To further understand the observed regioselectivity, an in-depth investigation into the reaction mechanism of the iridium-catalyzed hydroacylation reaction was carried out by preforming

Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides

• Kartik Temburnikar and
• Katherine L. Seley-Radtke

Beilstein J. Org. Chem. 2018, 14, 772–785, doi:10.3762/bjoc.14.65

• ribofuranose ring (which exists in equilibrium with the ring closed form), was exploited for C1' substitution using Grignard reagents [69]. Acid-catalyzed dehydration resulted in a diastereomeric mixture of C1'-disubstituted products 5 and 6 with an observed β/α ratio of 2:1 and 1:1, respectively. Similarily

Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols

• Katrina Tait,
• Oday Alrifai,
• Rebecca Boutin,
• Jamie Haner and
• William Tam

Beilstein J. Org. Chem. 2016, 12, 2189–2196, doi:10.3762/bjoc.12.209

• variety of substituents on cyclopropanated oxabenzonorbornadiene. With unsymmetrical C1-substituted cyclopropanated 7-oxabenzonorbornadienes, the regioselectivity of the reaction was excellent, forming only one regioisomer in all cases. Keywords: alcohol nucleophiles; C1 substitution; cyclopropanated

Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylates

• Michael Edmunds,
• Mohammed Abdul Raheem,
• Rebecca Boutin,
• Katrina Tait and
• William Tam

Beilstein J. Org. Chem. 2016, 12, 239–244, doi:10.3762/bjoc.12.25

• investigations into the effect C1 substitution of 1 would have on the reaction. The addition of a substituent at the bridgehead carbon renders the bicyclic structure unsymmetrical and alters the steric and electronic factors imposed on the incoming palladium–aryl complex, which could affect the reactivity and

• regioselectivity of the reaction. Two regioisomers are possible for this reaction based on whether the aryl group is added to carbon a or carbon b of 2 (Scheme 3). Our group recently investigated the effect of C1 substitution, with ethyl and methoxycarbonyl substituents, on the palladium-catalyzed ring-opening

• -opening of C1 substituted oxabenzonorbornadiene. Proposed mechanism for the palladium-catalyzed ring-opening reaction of oxanorbornadiene. Optimization of palladium catalyst, Lewis acid additive, and solvent. Effect of aryl iodide substitution on the ring-opening of oxanorbornadiene. Effect of C1

Synthesis of the B-seco limonoid core scaffold

• Hanna Bruss,
• Hannah Schuster,
• Rémi Martinez,
• Markus Kaiser,
• Andrey P. Antonchick and
• Herbert Waldmann

Beilstein J. Org. Chem. 2014, 10, 194–208, doi:10.3762/bjoc.10.15

• rearrangement with β-keto ester 60. These studies show that it might be necessary to oxygenate at C1 after the sigmatropic rearrangement because the C1 substitution seems to have major impact on the success of the rearrangement. Synthesis of the B-seco limonoid scaffold. Encouraged by the results of the