Cobalt-Mediated Macrocyclizations. Facile Synthesis of 2-Oxo Pyridinophanes via [2 + 2 + 2] Cycloaddition of α,ω-Diynes and Isocyanates
摘要:
Cobalt-mediated [2 + 2 + 2] cycloaddition of alpha,omega-diynes and isocyanates provides a direct approach to macrocyclic 2-oxopyridinophanes. This macrocyclization process, which proceeded most efficiently with aliphatic isocyanates, was conveniently performed at a moderate temperature (85degreesC) without irradiation or syringe-pump addition.
Synthesis of Macrocycles via Cobalt-Mediated [2 + 2 + 2] Cycloadditions
作者:Llorente V. R. Boñaga、Han-Cheng Zhang、Alessandro F. Moretto、Hong Ye、Diane A. Gauthier、Jian Li、Gregory C. Leo、Bruce E. Maryanoff
DOI:10.1021/ja045001w
日期:2005.3.1
omega-diynes underwent metal-mediated [2 + 2 + 2] cycloadditions with nitriles, cyanamides, or isocyanates in the presence of CpCo(CO)2 (Cp = cyclopentadienide) to yield pyridine-containing macrocycles, i.e., meta- and para-pyridinophanes, such as 5m/5p, 35m/35p, and 41m/41p. The regioselectivity of these reactions was affected by the length and type of linker unit between the alkyne groups, as well as
complex give [7]–[21]polyether cyclophanes in good yield. [8]–[9]Ester cyclophanes were also synthesized from the corresponding α,ω-diynes. The ratio of para-, meta-, and orthocyclophanes depends on the length and the structure of the α,ω-diyne tether chain, whilst the effect of concentration on the yield of polyether cyclophanes appears to be small. X-ray analysis revealed that a single crystal of [15]metacyclophane
Cobalt-Mediated Macrocyclizations. Facile Synthesis of 2-Oxo Pyridinophanes via [2 + 2 + 2] Cycloaddition of α,ω-Diynes and Isocyanates
作者:Llorente V. R. Boñaga、Han-Cheng Zhang、Diane A. Gauthier、Indrasena Reddy、Bruce E. Maryanoff
DOI:10.1021/ol030096c
日期:2003.11.1
Cobalt-mediated [2 + 2 + 2] cycloaddition of alpha,omega-diynes and isocyanates provides a direct approach to macrocyclic 2-oxopyridinophanes. This macrocyclization process, which proceeded most efficiently with aliphatic isocyanates, was conveniently performed at a moderate temperature (85degreesC) without irradiation or syringe-pump addition.