379685-58-2

Upstream product

• 542-92-7 cyclopenta-1,3-diene 
• 471242-92-9 2-[(E)-Benzylimino]-1-((1S,5R,7R)-10,10-dimethyl-3,3-dioxo-3λ⁶-thia-4-aza-tricyclo[5.2.1.0^1,5]dec-4-yl)-ethanone 
• 123191-45-7 (2R)-N-glyoxylbornane-10,2-sultam 
• 100-46-9 benzylamine 

Relevant academic research and scientific papers

Diastereoselectivity in the hetero [4+2] cycloaddition of cyclopentadiene to N-benzyliminoacetyl derivatives of (2R)-bornane-10,2-sultam and other chiral secondary alcohols

Various protonated chiral glyoxyloyl-α-imino-N-benzyl hetero-dienophiles have been examined in the diastereoselective exo-cycloaddition to cyclopentadiene at -78°C promoted by CF3CO2-BF3, a dissociated non-nucleophilic counter ion. The best π-facial selectivities were observed with (2R)-bornane-10,2-sultam (76% d.e.) and (2R)-10-dicyclohexylsulfonamoyl-isoborneol (80% d.e.) as chiral auxiliaries. These conditions were found to be superior in terms of yields and selectivities as compared to analogous aza-dienophiles treated with simple Lewis acids or under thermal conditions. Absolute configurations were assigned on the basis of an X-ray analysis of the major cycloadduct (3′S)-3a as well as by chiroptical comparison with the corresponding new amino alcohol (-)-(3S)-4a. Plausible transition states are briefly discussed on the basis of PM3 conformational calculations.