56909-85-4Relevant academic research and scientific papers
Is an iodine atom almighty as a leaving group for Bu3SnH-mediated radical cyclization? The effect of a halogen atom on the 5-endo-trig radical cyclization of N-vinyl-α-halo amides
Tamura, Osamu,Matsukida, Hana,Toyao, Atsushi,Takeda, Yoshifumi,Ishibashi, Hiroyuki
, p. 5537 - 5545 (2007/10/03)
The effect of a halogen atom as a leaving group on Bu3SnH-mediated 5-endo-trig radical cyclization of N-(cyclohex-1-enyl) α-halo amides was examined. The cyclization of α-chloro amides occurred with a high degree of efficiency, whereas the corresponding α-iodo congeners gave only limited quantities of cyclization products. A detailed study revealed that these phenomena could be attributed to the initial conformations of α-halo amides. The cyclizing ability of α-iodo amides can be restored with Bu3SnCl or Bu3SnF as an additive. The cyclization of an α-iodo amide in the presence of Bu3SnF could be applied to a short-step synthesis of lycoranes featuring sequential 5-endo-trig and 6-endo-trig radical cyclizations.
The use of an iodine atom as a leaving group for Bu3SnH-mediated 5-endo-trig radical cyclization of α-halo amides is not recommended
Ishibashi,Matsukida,Toyao,Tamura,Takeda
, p. 1497 - 1499 (2007/10/03)
Bu3SnH-mediated 5-endo-trig radical cyclization of N-(cyclohex-1-enyl) α-chloro amides occurred with a high degree of efficiency, whereas the corresponding α-iodo congeners gave only limited quantities of the cyclization products. The cyclizing
Formation of Five-membered Lactams by 5-Endo-Trigonal Radical Cyclisations of 2-Chloro-N-(cycloalk-1-enyl)acetamides: New Synthesis of Erythrinane Skeleton
Sato, Tatsunori,Nakamura, Nobuyuki,Ikeda, Keiko,Okada, Michiyo,Ishibashi, Hiroyuki,Ikeda, Masazumi
, p. 2399 - 2408 (2007/10/02)
Free-radical cyclisations of a range of 2-chloro-N-(cycloalk-1-enyl)acetamides have been examined.The enamide 5, upon treatment with Bu3SnH in the presence of azoisobutyronitrile, underwent cyclisation via the carbamoylmethyl radical 6 in a 'disfavoured'
Radical cyclizations of N-vinylic α-chloroacetamides. 5-Endo-trig and 4-exo-trig cyclizations
Ishibashi,Nakamura,Sato,Takeuchi,Ikeda
, p. 1725 - 1728 (2007/10/02)
Bu3SnH mediated radical cyclizations of N-vinylic α-chloroacetamides proceeded in a ''disfavored'' 5-endo-trig manner to give five-membered lactams. Some exceptions where the 4-exo cyclization predominates are also described.
