Cobalt(I)-сatalyzed [6π+2π]-сycloadditions of 1,2-dienes to 1,3,5,7-cyclooctatetraene

Transition metal catalyzed [6 + 2] cycloadditions

“…D'yakonov et al have accomplished the Co( i ) catalyzed [6 + 2]-cycloadditions of 1,3,5,7-cyclooctatetraene 26 (COTT) with functionalized terminal allenes 27a–e in the presence of CoI 2 /dppe/Zn/ZnI 2 catalytic system using 1,2-dichloroethane as solvent at 60 °C to afford ( E )-bicyclo[4.2.2]deca-2,4,7-trienes 28a–e in good yields (78–85%; Scheme 12 ). 41 The reactions are gauged using varied reaction and catalytic system. It is observed that CoI 2 or ZnI 2 alone do not conceive the reactions even at elevated temperature (100 °C).…”

“…The [6 + 2] cycloadditions of COTT26 with 1,2-cyclononadiene 27f under similar reaction conditions afford tricyclo[9.4.2.0]heptadeca-2,12,14,16-tetraene 28f in 65% yield. Interestingly, the reactions also proceed further to produce regio- and strereomeric bis-adduct mixture 29a and 29b in total yield of 30% 41 ( Scheme 13 ).…”

Bran-New Four-Molecule and Five-Molecule Cascade Reactions for One-Pot Synthesis of Pyrano[3,2-c]chromen-5-ones and Spiro[benzo[b][1,4]diazepine-2,2′-pyrano[3,2-c]chromen]-5′-ones under Catalyst- and Solvent-Free Conditions

“… 3 , 4 As a result, over the past decade, remarkable advances have been made on this topic. 5 − 9 Despite this compelling progress, most studies often suffer from one or more of the following disadvantages, such as the compulsive dependence on heavy metal or expensive metal catalysts, 10 and the utilization of harmful 11 and/or expensive reagents. 12 Undoubtedly, the further development of mild, efficient, and general MCRs for the direct assembly of a key structural motif is still highly desired.…”

“…Multi-component reaction (MCR) has emerged as one of the most popular and powerful approaches for the one-pot synthesis of important natural products, organic building blocks, and pharmaceutical intermediates. , Because of the reduced number of reaction steps and simple operation, MCR usually leads to reduced waste of the starting materials and acceptable yields of the corresponding products in a step/atom-economical and environmentally benign fashion. , As a result, over the past decade, remarkable advances have been made on this topic. − Despite this compelling progress, most studies often suffer from one or more of the following disadvantages, such as the compulsive dependence on heavy metal or expensive metal catalysts, and the utilization of harmful and/or expensive reagents . Undoubtedly, the further development of mild, efficient, and general MCRs for the direct assembly of a key structural motif is still highly desired …”