Diastereoselective aziridination of cyclic dienes with 3-acetoxyaminoquinazolin-4(3H)-ones: competitive formation of insertion products from cyclohexadienes
作者:Robert S Atkinson、Christopher K Meades
DOI:10.1016/s0040-4039(00)01328-9
日期:2000.9
highly diastereoselectively: the corresponding aziridination product of cyclohexa-1,3-diene is formed less diastereoselectively and is accompanied by a by-product 9 from formal insertion into an allylic CH bond, a previously unobserved reaction type for 3-acetoxyaminoquinazolinones.
Aziridination of cyclic dienes with enantiopure 3-acetoxyaminoquinazolin-4(3H)-ones
作者:Robert S. Atkinson、Christopher K. Meades
DOI:10.1039/b102592a
日期:——
Aziridination of cyclopentadiene and cyclohepta-1,3-diene with (S)-3-acetoxyamino-2-(3-hydroxy-2,2-dimethylpropyl)quinazolin-4(3H)-one 6 (Q1NHOAc) in the presence of titanium(IV) tert-butoxide in dichloromethane takes place highly diastereoselectively: X-ray structure determinations show that the preferred sense of diastereoselectivity in both cases is the same as that previously found for aziridination of butadiene with 6. Aziridination of cyclohexa-1,3-diene with 6 was less diastereoselective in dichloromethane solution but highly diastereoselective in acetonitrile: in this solvent two diastereoisomeric cis-4-(Q1-amino)cyclohexen-3-ols 27 and 28 were also obtained as by-products. The same two amino
alcohols were obtained by ring-opening of the aziridine with acid and were each converted into Q1-free oxazolidinones having optical rotations which were similar in magnitude but opposite in sign.
作者:Stacy W Remiszewski、Joongik Yang、Steven M Weinreb
DOI:10.1016/s0040-4039(00)84393-2
日期:1986.1
N-Sulfinyl carbamates prepared from phenylmenthol () and (+) -camphor- derived alcohol display high enantioselectivity in TiCl4 catalyzed [4+2] cycloadditions with 1,3-cyclohexadiene.
Asymmetric N-sulfinyl dienophile Diels–Alder cycloadditions using chiral Ti(IV)-based Lewis acids
作者:Annette Bayer、Odd R Gautun
DOI:10.1016/s0040-4039(00)00480-9
日期:2000.5
Enantioselective Diels–Alder reactions of 1,3-cyclohexadiene with N-sulfinylbenzyl carbamate (1a) or N-sulfinyl-p-toluenesulfonamide (1b) promoted by chiral Ti(IV)-based Lewis acids are reported. The endo-adducts were obtained in 15–76% ee.