Diastereoselective Multicomponent Cascade Reaction Leading to [3.2.0]-Heterobicyclic Compounds
摘要:
A general three-component triple cascade reaction through an iminium-enamine-iminium sequential activation initiated by a hetero-Michael addition to alpha,beta-unsaturated aldehydes affords [3.2.0]heterobicycles in high diastereoselectivity. The rate and diastereoselectivity of the reaction depended on the (E)-4-heterocrotonate and size of the secondary amine. The enantiomers of the major diastereoisomer of oxa- and azabicyclo[3.2.0]heptane derivatives were separated by enzymatic kinetic resolution with immobilized Candida antarctica Lipase B (CALB), with E values up to 153. The absolute configuration of the nonacylated enantiomer of oxabicyclo[3.2.0]heptane was determined by single crystal X-ray analysis.
Diastereoselective Multicomponent Cascade Reaction Leading to [3.2.0]-Heterobicyclic Compounds
摘要:
A general three-component triple cascade reaction through an iminium-enamine-iminium sequential activation initiated by a hetero-Michael addition to alpha,beta-unsaturated aldehydes affords [3.2.0]heterobicycles in high diastereoselectivity. The rate and diastereoselectivity of the reaction depended on the (E)-4-heterocrotonate and size of the secondary amine. The enantiomers of the major diastereoisomer of oxa- and azabicyclo[3.2.0]heptane derivatives were separated by enzymatic kinetic resolution with immobilized Candida antarctica Lipase B (CALB), with E values up to 153. The absolute configuration of the nonacylated enantiomer of oxabicyclo[3.2.0]heptane was determined by single crystal X-ray analysis.
A novel multicomponent cascade reaction led to the formation of a strained 3-azabicyclo[3.2.0]heptane derivative 4. The unstable ester 4 was reduced in a one-pot procedure to a stable alcohol 6. The formation of the bicyclic product is highlydiastereoselective, predominantly affording one diastereoisomer. The obtained azabicycloheptanes are important pharmacophores.
New 3-azabicyclo[3.2.0]heptane derivatives were synthesized using a multicomponent reaction. Racemic compounds were efficiently resolved by kinetic resolution with immobilized lipase B of Candida antarctica (Novozym 435). The obtained compounds demonstrated greater binding affinity at D-2L and D-3 dopamine receptors compared to D-1 binding sites, and individual enantiomers of the same compound possessed distinct affinities. (C) 2012 Elsevier Masson SAS. All rights reserved.
Diastereoselective Multicomponent Cascade Reaction Leading to [3.2.0]-Heterobicyclic Compounds
A general three-component triple cascade reaction through an iminium-enamine-iminium sequential activation initiated by a hetero-Michael addition to alpha,beta-unsaturated aldehydes affords [3.2.0]heterobicycles in high diastereoselectivity. The rate and diastereoselectivity of the reaction depended on the (E)-4-heterocrotonate and size of the secondary amine. The enantiomers of the major diastereoisomer of oxa- and azabicyclo[3.2.0]heptane derivatives were separated by enzymatic kinetic resolution with immobilized Candida antarctica Lipase B (CALB), with E values up to 153. The absolute configuration of the nonacylated enantiomer of oxabicyclo[3.2.0]heptane was determined by single crystal X-ray analysis.