Aza-Morita-Baylis-Hillman reactions and cyclizations of conjugated dienes activated by sulfone, ester, and keto groups.
The aza-Morita-Baylis-Hillman reactions of aldimines 2 with several activated conjugated dienes were found to proceed smoothly in DMF in the presence of 3-hydroxyquinuclidine (HQD). Imines 2 reacted with 1-(p-toluenesulfonyl)-1,3-butadiene (3), methyl 2,4-pentadienoate (6), hexa-3,5-dien-2-one (7), and 1-phenylpenta-2,4-dien-1-one (8) to afford adducts 4, 13, 14, and 15, respectively. While products 4, 13, and 15 were formed as E,Z mixtures, adducts 14 were obtained as essentially pure E-isomers. Cyclization of the E-isomers of the products derived from the dienyl sulfone 3 and the dienoate ester 6 occurred via intramolecular conjugate addition under base-catalyzed conditions to afford functionalized piperidines 5 and 16, respectively. The aza-Morita-Baylis-Hillman reaction and subsequent cyclization of the imine 2a with 3 were also carried out as a one-pot reaction, while the reaction mixture was simultaneously irradiated at 300 nm to effect the photoisomerization of the unreactive Z-adduct of the corresponding 4 to the more reactive E-isomer.
Sorbetti
Jovina M
JM
Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
Clary
Kristen N
KN
Rankic
Danica A
DA
Wulff
Jeremy E
JE
Parvez
Masood
M
Back
Thomas G
TG
D002625:Chemistry, Organic / Q000379:methods*; D004952:Esters / Q000737:chemistry*; D006844:Hydrocarbons, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D007097:Imines / Q000737:chemistry; D007536:Isomerism; D007651:Keto Acids / Q000737:chemistry; D011090:Polyenes / Q000138:chemical synthesis / Q000737:chemistry*; D011812:Quinuclidines / Q000737:chemistry; D013450:Sulfones / Q000737:chemistry*
D004952:Esters; D006844:Hydrocarbons, Cyclic; D007097:Imines; D007651:Keto Acids; D011090:Polyenes; D011812:Quinuclidines; D013450:Sulfones