Unexpected Zirconium‐Mediated Multicomponent Reactions of Conjugated 1,3‐Butadiynes and Monoynes with Acyl Cyanide Derivatives

Abstract

Going ber(zirc): zirconium-butadiyne complexes react with acyl cyanide derivatives through diverse reaction pathways. The complexes react with two molecules of carbamoyl cyanide to form 1,4-benzodiazepin-2-one-derivatives containing azazirconacycles. Reactions with either aroyl cyanides or alkyl cyanoformates lead to azazirconacyclopentenes containing a quaternary carbon center.

Reactions of Group 4 Metallocene Complexes with Mono‐ and Diphenylacetonitrile: Formation of Unusual Four‐ and Six‐Membered Metallacycles

“…As a result, a new C4C5 bond (1.507(3) Å) is created. Such insertion reactions have already been established in zirconium‐mediated multi‐component reactions of butadiynes with nitriles8 or carbamoyl cyanides 30. The subsequent coupling of N1 and C2 leads to the formation of the five‐membered cycle in 8 .…”

Zirconium‐Mediated Multicomponent Reactions of 1,3‐Butadiynes with Ylidenemalononitriles to Form Functionalized 1,8‐Naphthyridine and Cyclopenta[b]pyridine Derivatives

“…The resulting zirconocene–butadiyne complexes can be described as a highly strained zirconacyclocumulene 3 , which is possibly in equilibrium with the three‐membered alkynylzirconacyclopropene 2 , although the equilibrium is shifted towards 3 (Table 1). Zirconacyclocumulene 3 undergoes a series of interesting and unusual multicomponent reactions with aldehydes,8a carbamoyl cyanides,8b aroyl cyanides,8b and nitriles 8c. Treatment of TIPS‐substituted zirconium species 2 a / 3 a , derived from the 1,4‐bis[tri(isopropyl)silyl]buta‐1,3‐diyne 1 a , with 4 equivalents of 2‐benzylidenemalononitrile at room temperature for 5 h, afforded the α‐alkynylazazirconacycle 4 a incorporating a hexahydro‐1,8‐naphthyridine skeleton in 67 % yield as a mixture of two diastereomers with a ratio of 7.2:1 (Table 1, entry 1).…”

A new synthesis of versatile indolyl-3-carbonylnitriles

“…Cu(I)CN, KCN or TMSCN, followed by oxidation to regenerate the carbonyl if necessary. 5,6,[16][17][18][19] In an effort to avoid the use of potentially dangerous sources of cyanide, various research groups have exploited the conversion of activated oximes into nitriles and carbonyl nitriles respectively. 20,21 Moreover, aryl amides are known to dehydrate in the presence of thionyl chloride to give the corresponding aryl nitriles 22 and it was reasoned this could possibly be applied to the synthesis of 1 from indolyl-3-α-oxoacetamide (4).…”