Interaction of Aryloxychlorocarbenes with Acetylenedicarboxylate:  Novel Formation of Polyfunctional Butadienes and 8-Oxatricyclo[3.2.1.0^2.4]oct-6-enes

Abstract

The interaction of aryloxychlorocarbenes with dialkyl acetylenedicarboxylates has been examined. Thermolyses of 3-aryloxy-3-chlorodiazirines in the presence of acetylenedicarboxylate resulted in the formation of unexpected polyfunctional 1,3-butadienes and 8-oxatricyclo[3.2.1.0(2.4)]oct-6-enes or of 2-aryoxycarbonylmaleates dependent upon reaction conditions. This work confirmed the nucleophilicity of aryloxychlorocarbenes and underlined their synthetic potential.

The multicomponent reaction of imidazo[1,5-a]pyridine carbenes with phthalaldehydes and dimethyl acetylenedicarboxylate: a facile construction of benzo[d]furo[3,2-b]azepines

“…Anal. Calcd for C 24 H 24 N 2 O 6 : C 66.04, H 5.54,N 6.42;Found: C 66.08,H 5.60,6. 8.30 (dd,J = 4.7,0.7 Hz,1H),7.57 (d,J = 7.9 Hz,1H),7.47 (dt,J = 7.7,1.7 Hz,1H),2H),7.07 (dt,J = 7.4,1.1 Hz,1H), 7.01 (d, J = 7.9 Hz, 1H), 6.96 (dd, J = 7.3, 4.9 Hz, 1H), 5.62 (t, J = 6.3 Hz, 1H), 5.18 (d, J = 5.4 Hz, 1H), 5.07 (d, J = 7.0 Hz, 1H), 3.90 (s, 3H), 3.87-3.94 (m, 1H), 3.86 (s, 3H), 1.24 (d, J = 6.4 Hz, 3H), 1.04 (d, J = 6.6 Hz, 3H); 13 C NMR (100 MHz, DMSO-d 6 ) d (ppm) 164. 9, 160.4, 157.5, 148.6, 137.7, 137.5, 136.8, 136.1, 132.3, 131.1, 127.9, 127.3, 125.7, 123.0, 121.3, 120.3, 119.9, 74.0, 61.9, 53.2, 53.0, 52.3, 22.0, 21.6 4.6 Hz,1H),7.74 (s,1H),7.55 (s,1H),7.41 (t,J = 7.8,1H),7.20 (d,J = 7.9 Hz 1H), 6.90 (t, J = 6.0 Hz, 1H), 6.33 (br,1H),5.14 (d,J = 1.7 Hz,1H),4.67 (s,1H),4.03 (s,3H),3.92 (s,3H),1H),2.26 (s,1H),2.20 (s,1H),1.32 (s,…”

“…Our interests in nucleophilic carbenes and their applications in organic synthesis 6 have led us to investigate multicomponent reactions of N-heterocyclic carbenes. 5 Our attention had been drawn to imidazo [1,5-a]pyridine-1-ylidenes and imidazo [1,5-a]pyridine-3-ylidenes, the C,N-substituted and N,N-substituted imidazo [1,5a]pyridine carbenes reported in 2005 by Lassaletta et al 7 and Glorius et al 8 Both types of imidazo [1,5-a]pyridine carbenes have been shown to be strong C-ligands to Ag, Rh, Ir, Pd cations and elemental Se; 7,8 however, their reactions and applications as organic intermediates remain largely unexplored.…”

Electron‐Rich Oxycarbenes: New Synthetic and Catalytic Applications beyond Group 6 Fischer Carbene Complexes

“…[39] In 2005, Cheng et al reported reactions of oxycarbene precursor 7.10 with acetylene dicarboxylate 7.12 to afford 2-aryloxycarbonyl maleates, polysubstituted 1,3butadienes, or 8-oxatricyclo[3.2.1.0 2,4 ]oct-6-enes as the major products depending on the reaction temperatures (Scheme 7E). [40] The authors proposed that aryloxychlorocarbene 7.10 was generated from oxycarbene precursor 7.11, and then reacted with acetylenedicarboxylate 7.12 to obtain cyclopropene 7.13. Intermediate 7.14 was generated through the [2+1] cyclization of cyclopropene 7.13 with another aryloxychlorocarbene intermediate 7.11.…”

Double Duty for Cyanogen Bromide in a Cascade Synthesis of Cyanoepoxides

“…Under different conditions, the Br À C bond can be cleaved in a diverse manner (Scheme 1, Modes I-IV). [3] In the von Braun reaction, BrCN acts as an equivalent of both CN + and Br À by fragmenting tertiary amines into cyanamides and alkylbromides (Mode IV). [1] In the reaction with vinyltellrium bromide, cyanogen bromide acted as an equivalent of a cyanide anion, and converts vinyltellurium bromide into a vinyltellurium cyanide (Mode II).…”

“…[2] When reacted with primary or secondary amines or alcohols, cyanogen bromide behaves as an equivalent of CN + , and gives rise to cyanamides or cyanates (Mode III). [3] In the von Braun reaction, BrCN acts as an equivalent of both CN + and Br À by fragmenting tertiary amines into cyanamides and alkylbromides (Mode IV). [4,5] Herein, we report an unprecedented Mode V, in which cyanogen bromide works as an equivalent of Br + and CN À in a one-pot transformation of ketones into cyanoepoxide derivatives (Mode V).Our research group has recently demonstrated that alkynyl bromides can act as equivalents of both Br + and alkynyl anions in a highly efficient, one-pot conversion of ketones into alkynylepoxides.…”