作者:Tirthankar Ghosh、Henry L. Gingrich、Carolyn K. Kam、Edward C. Mobraaten、Maitland Jones
DOI:10.1021/ja00004a036
日期:1991.2
A carborane version of dehydrobenzene, 1,2-dehydro-o-carborane, has been generated from (2-bromo-o-carboranyl) lithium. This new intermediate undergoes the ene reaction as well as 2+2 and 2+4 cycloadditions. The 2+2 cycloaddition is nonstereospecific, whereas the 2+4 cycloaddition likely proceeds with retention of stereochemistry
Carboryne (1,2-dehydro-o-carborane), in situ generated from the precursor 1-iodo-2-lithiocarborane, reacted with alkylbenzenes to give two regioisomers of the [4 + 2] cycloadducts as the major products in moderate to good yields, in which the steric factors play an important role in the regioselectivity. Minor products derived from benzylic C–H insertion reaction, annulation reaction, tandem [4 + 2]