Tandem Cyclization of Alkynylmetals Bearing a Remote Leaving Group via Cycloalkylidene Carbenes
摘要:
Treatment of terminal alkynes bearing a remote leaving group with MNR2 (M = Li, Na, K) gives bicyclo[n.3.0]-1-alkenes (n = 3, 4). The tandem cyclization proceeds through a mechanism involving exo-cyclization of an alkynylmetal intermediate and intramolecular C-H insertion of the resulting carbenoid.
Iodine-Atom-Transfer-Type Carbocyclization of 2-(2-Propynyloxy)ethyl Iodides Involving a Lithium Alkylidene Carbenoid Intermediate
作者:Toshiro Harada、Chie Kitano、Kenta Mizunashi
DOI:10.1055/s-2007-973907
日期:2007.4
In the presence of 1-hexynyllithium, 2-(2-propynyl-oxy)ethyliodides undergo carbocyclization with 1-iodo-1-hexyne to afford 3-(diiodomethylene)tetrahydrofurans in an atom-economical manner with incorporation of the two iodine atoms from the substrates and the reagent.