ChemInform Abstract: Stereodivergent Synthesis of 1,3‐syn‐ and anti‐Tetrahydropyrimidinones.

Abstract

Depending on the choice of solvent either syn‐ or anti‐diastereomers can be obtained as protected 1,3‐diamine structures.

Stereodivergent Catalysis

“…The diastereodivergent intramolecular Pd-catalyzed allylic amination of ureas 678 has been achieved under different reaction conditions. 588 In THF, cis-1,3-tetrahydropyrimidones 679 were formed with de up to 90%, whereas in CH 2 Cl 2 1,3trans-products 679 were obtained also with de up to 90% (Scheme 258). These products were further transformed into syn-and anti-1,3-diamines.…”

Stereodivergent Palladium- and Rhodium-Catalyzed Intramolecular Addition of Tosylureas to Allenes: Diastereoselective Synthesis of Tetrahydropyrimidinones

“…Reductive cleavage of the tosyl group gave 4 in quantitative yield, and consequent treatment with aqueous HCl allows access to the valuable 1,3-diamine 5-hydrochloride. 5 Hydrogenation of the double bond affords aliphatic When isolated 2a was subjected to Rh-catalysis conditions, no change in diastereomeric ratio was observed. However, after subjecting 3a to palladium-catalysis conditions, almost quantitative corrosion of the allylic stereocenter in favor of the anti-isomer 2a was observed after 16 h. This observation is in accordance with conducted DFTcalculations (BP86/dev2svp), predicting 2a to be 2.4 kcal more stable than 3a, therefore 2a being the thermodynamic and 3a being the kinetic product of the described cyclization (Scheme 4).…”

“…Menche reported a Pd-catalyzed intramolecular allylic substitution of allylcarbonates, resulting in 1,3-disubstituted tetrahydropyrimidinones. 5 Variation of the solvent allowed stereodivergent synthesis of syn-and antitetrahydropyrimidinones in excellent yields and diastereoselectivities. A powerful isomerization/amination method was published by White, who applied Pd-catalyzed C−H-oxidation in allylic position to access 1,2-imidazolidinones.…”