Unexpected formation of new fluoroboranes from the reaction of NMe4B3H8 with BF3 and MeC CH: exo-2-FB4H9 and trans-MeCH CHBF2

The new fluoroboranes exo-2-FB4H9 1 and trans-MeCH=CHBF2 2 have been obtained unexpectedly and in good yield from the reaction of tetramethylammonium octahydrotriborate (NMe4B3H8) with boron trifluoride and propyne (MeC=CH).