37734-08-0Relevant academic research and scientific papers
Origin of the Base-Dependent Facial Selectivity in Annulation Reactions of Nazarov-Type Reagents with Unsaturated Indolo[2,3-a]quinolizidine Lactams
Estarellas, Carolina,Arioli, Federica,Pérez, Maria,Are, Celeste,Hevia, David,Molins, Elies,Luque, F. Javier,Bosch, Joan,Amat, Mercedes
, p. 3969 - 3979 (2017)
Methyl-substituted Nazarov reagent 4 reacts stereoselectively with Nind-Boc indoloquinolizidine lactams to give the expected 3-H/15-H cis pentacyclic yohimbine-type adducts when using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the base. However, a dramatic change of the facial selectivity was observed when the reaction was performed in the presence of Cs2CO3, leading to the corresponding trans adducts. This annulation is the key step of a stereocontrolled synthesis of the 17a-carba analogue of the heteroyohimbine alkaloid akuammigine. Theoretical calculations were used to rationalize the facial selectivity of these double Michael addition reactions.
Synthesis of β-Amino and β-Methoxy Ketones by Lewis Acids Promoted β-Substitution Reactions of βγ,-Unsaturated Ketones
Lee, Adam Shih-Yuan,Wang, Shu-Huei,Chang, Yu-Ting,Chu, Shu-Fang
, p. 2359 - 2363 (2007/10/03)
A reaction mixture of β,γ-unsaturated ketone and BF 3·OEt2 in CH3OH was stirred at room temperature and β-methoxy ketone was produced in high yield. The β-amino ketone was obtained as the major product from a reaction mixture of β,γ-unsaturated ketone, AlCl3 and Ts-NH2 in CH2Cl2 at room temperature. This Lewis acid promoted β-substitution reaction mechanism was proposed as that the process occurred via in situ isomerization of β,γ-unsaturated ketone to α,β-unsaturated ketone followed by the 1,4-addition reaction.
