On the control of secondary carbanion structure utilising ligand effects during directed metallation

• Andrew E. H. Wheatley,
• Jonathan Clayden,
• Ian H. Hillier,
• Alison Campbell Smith,
• Mark A. Vincent,
• Laurence J. Taylor and
• Joanna Haywood

Beilstein J. Org. Chem. 2012, 8, 50–60, doi:10.3762/bjoc.8.5

• (L = PMDTA, DGME; DGME = diglyme) and also, under kinetic control, the remarkable hemi-solvated ortho-lithiate (Scheme 4). This development allowed thermodynamic lithiate 5-Lil·PMDTA to be successfully used to generate a variety of benzamides bearing quaternary C-centres at the aromatic 2-position

Regioselectivity in the multicomponent reaction of 5-aminopyrazoles, cyclic 1,3-diketones and dimethylformamide dimethylacetal under controlled microwave heating

• Kamal Usef Sadek,
• Ramadan Ahmed Mekheimer,
• Tahany Mahmoud Mohamed,
• Moustafa Sherief Moustafa and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2012, 8, 18–24, doi:10.3762/bjoc.8.3

• afforded the corresponding pyrazolo[4,3-c]quinazolin-9-ones [20]. It was concluded that, under ambient and neutral conditions, the reaction proceeds under kinetic control, and the Biginelli-type dihydropyrimidines are the predominant isomers. Increasing the reaction temperature in the presence of

2-Phenyl- tetrahydropyrimidine- 4(1H)-ones – cyclic benzaldehyde aminals as precursors for functionalised β²-amino acids

• Markus Nahrwold,
• Arvydas Stončius,
• Anna Penner,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2009, 5, No. 43, doi:10.3762/bjoc.5.43

• reaction was carried out under kinetic control, its moderate trans-selectivity contrasts to the high cis-selectivity observed for the thermodynamically controlled cyclocondensation of potassium asparaginate and aliphatic aldehydes [25][27][28][31][34][35]. En route to the target compound (R)-4, the allyl

Reagent controlled addition of chiral sulfur ylides to chiral aldehydes

• Varinder K. Aggarwal and
• Jie Bi

Beilstein J. Org. Chem. 2005, 1, No. 4, doi:10.1186/1860-5397-1-4

• reacted much more reversibly as evidenced by the higher trans selectivity (96: 4), the C2 control was similar (84:16) (8a+8c: 8b) to the reaction under kinetic control (Table 1, entry 2). This indicated that the rate of bond rotation or the rate of the ring closure of the two anti betaines (k5 and k7 or