A microwave-enhanced, solventless Mannich condensation of terminal alkynes and secondary amines with para-formaldehyde on cuprous iodide doped alumina
作者:George W. Kabalka、Li-Li Zhou、Lei Wang、Richard M. Pagni
DOI:10.1016/j.tet.2005.10.049
日期:2006.1
A microwave-enhanced, solventless Mannich condensation of terminal alkynes and secondary amines with para-formaidehyde on cuprous iodide doped alumina has been developed. beta-Aminoalkynes are generated in good yields. The reaction can be extended to include a cyclization, which affords 2-substituted benzo[b]furans. The chemoselectivity of the reaction indicates that terminal alkynes are much more reactive than enolizable ketones under the reaction conditions. (c) 2005 Elsevier Ltd. All rights reserved.
Sonogashira coupling and cyclization reactions on alumina: a route to aryl alkynes, 2-substituted-benzo[b]furans and 2-substituted-indoles
作者:George W Kabalka、Lei Wang、Richard M Pagni
DOI:10.1016/s0040-4020(01)00774-8
日期:2001.9
A solventless, microwave-enhanced Sonogashira coupling reaction of aromatic iodides with terminal alkynes on potassium fluoride doped alumina in the presence of palladium powder, cuprous iodide, and triphenylphosphine has been developed. The reaction can be utilized to prepare aryl alkynes in excellent yields. The coupling of o-iodophenol with terminal alkynes leads to the formation 2-substituted-benzo[b]furans. Whereas the coupling of o-iodoanilines with terminal alkynes generates indole products. An in situ desilylation reaction was also developed. (C) 2001 Elsevier Science Ltd. All rights reserved.
Haloboration of
<i>o</i>
‐Alkynyl Phenols Generates Halogenated Bicyclic‐Boronates**
作者:Kang Yuan、Michael J. Ingleson
DOI:10.1002/anie.202301463
日期:——
O-directed alkyne trans-haloboration using BX3 (X=Cl or Br) leads to C4-halogenated benzoxaborinines that are useful intermediates for accessing the core structure found in bicyclic boronate based β-lactamase inhibitors. A computational study identified two viable mechanisms to furnish the trans-haloboration products.