The first example of the FBW rearrangement using of lanthanum metal and a catalytic amount of iodine was disclosed. When gem-diiodo- and gem-dibromoalkenes were treated with lanthanum metal in the presence of a catalytic amount of iodine, the reductive dehalogenation of these compounds smoothly proceeded to produce the corresponding alkynes in moderate to good yields.
Dehydrative Fragmentation of 5-Hydroxyalkyl-1<i>H</i>-tetrazoles: A Mild Route to Alkylidenecarbenes
作者:Duncan J. Wardrop、John P. Komenda
DOI:10.1021/ol300276p
日期:2012.3.16
The development of a mild, base-free method for the generation of alkylidenecarbenes is reported. Treatment of 5-hydroxyalkyl-1H-tetrazoles with carbodiimides generates products arising from the 1,2-rearrangement or [1,5]-C–H bond insertion of a putative alkylidenecarbene. Formation of this divalent intermediate is proposed to occur by way of a tetraazafulvene, which undergoes extrusion of 2 mol of
Generation of alkylidenecarbenes by the alkenation of carbonyl compounds with lithiotrimethylsilyldiazomethane
作者:Susumu Ohira、Keiji Okai、Takanori Moritani
DOI:10.1039/c39920000721
日期:——
The reaction of carbonyl compounds and lithiotrimethylsilyldiazomethane, which generate alkylidenecarbenes, gives a terminal acetylene from an aldehyde and cyclopentene derivatives from ketones.