02014nas a2200205   4500008004100000022001400041245016000055210006900215260000800284300001400292490000700306520122100313100002001534700001701554700002801571700002401599700003201623700001901655856013401674       2026                        eng d  a1477-922600aReactions of saturated NHC·boranes with electron-deficient alkynes and alkenes. borirane formation, their reactivities, and coupling of tetracyanoethylene0 aReactions of saturated NHC boranes with electrondeficient alkyne  cJUN  a8356-83650 v553 a<p>
	In this study, we describe the reactions of five- and six-membered saturated N-heterocyclic carbene boranes (NHC &amp; centerdot;BH3) with electron-deficient alkenes and alkynes. Notably, both five- and six-membered saturated NHCs form boriranes upon the reaction of NHC &amp; centerdot;BH3 with dimethyl acetylene dicarboxylate (DMAD). However, their reactivity with HCl differs: the five-membered saturated NHC-stabilized borirane undergoes ring opening in toluene/THF, whereas the six-membered saturated NHC-stabilized borirane undergoes ring expansion, forming exclusively a boralactone irrespective of solvent. Interestingly, when acetonitrile is used as a solvent, the five-membered saturated NHC-stabilized borirane yields both ring-opening and ring-expansion products. To remove the hydrogen attached to the boron atom in boriranes, we reacted the five-membered saturated NHC-stabilized borirane with AlCl3 and B(C6F5)(3), resulting in azaborolium cation or adduct formation, respectively. Transitioning from an electron-deficient alkyne to an alkene, the reaction of six-membered saturated NHC &amp; centerdot;BH3 with tetracyanoethylene (TCNE) led to the unusual coupling of two TCNE molecules.</p>
1 aAmrutha, P., R.1 aKundu, Gargi1 aGanesh, Vemuri, Lakshmi1 aGonnade, Rajesh, G.1 aGopakumar, Gopinadhanpillai1 aSen, Sakya, S.  uhttps://library.ncl.res.in/content/reactions-saturated-nhc%C2%B7boranes-electron-deficient-alkynes-and-alkenes-borirane-formation