A nBuLi‐Mediated, Expeditious and Stereoselective Ring‐Opening Rearrangement of (Arylmethylene)cyclopropane‐1,1‐dicarboxylates

Abstract

We report herein an nBuLi‐mediated, expeditious, ring‐opening rearrangement of (arylmethylene)cyclopropane 1,1‐diesters to prepare 1,3‐diene derivatives with good stereoselectivity. The reaction mechanism has also been discussed.

Indium(III)-Catalyzed Knoevenagel Condensation of Aldehydes and Activated Methylenes Using Acetic Anhydride as a Promoter

“…The general procedure was followed with ( E )-cinnamaldehyde ( 8d ; 79.3 mg, 0.600 mmol) and dimethyl malonate ( 2a ; 79.3 mg, 0.660 mmol) for 8 h to yield a yellow solid ( 9da ; 116.7 mg, 79%): mp 64–65 °C; 1 H NMR (500.2 MHz, CDCl 3 ) δ 3.81 (s, 3 H, OC H 3 ), 3.90 (s, 3 H, OC H 3 ), 7.04 (d, J = 16.0 Hz, 1 H, PhC H ), 7.27 (dd, J = 15.0, 15.5 Hz, 1 H, PhCHC H ), 7.32–7.38 (m, 3 H, Ar H ), 7.50 (d, J = 6.0 Hz, 2 H, Ar H ), 7.56 (d, J = 11.5 Hz, 1 H, PhCHCH–C H C); 13 C NMR (125.8 MHz, CDCl 3 ) δ 52.2, 52.3, 123.1, 123.9, 127.8, 128.8, 129.8, 135.4, 145.1, 146.1, 165.0, 165.6; HRMS (EI-Quadrupole) calcd for [M] + (C 14 H 14 O 4 ) m / z 246.0892, found 246.0881. The spectroscopic data of 9da were in good agreement with that reported in the literature …”

Progress in the Synthesis and Transformations of Alkylidenecyclopropanes and Alkylidenecyclobutanes

“…The dimethyl (arylmethylene)­cyclopropane-1,1-dicarboxylates, of general structure 387 , undergo an unexpected ring-opening rearrangement when treated with n -BuLi. The result is a mixture of Z / E -configured buta-1,3-dienes 665 in which the Z isomer is the most abundant (Scheme ) …”

Synthesis of Nitrogen-Substituted Methylenecyclopropanes by Strain-Driven Overman Rearrangement of Cyclopropenylmethyl Trichloroacetimidates

“…[1][2][3][4] Typically, these highly strained systems are susceptible to ring-opening reactions [5][6][7][8][9][10][11][12][13][14][15][16][17], cycloaddition reactions [18][19][20][21][22][23] and ring-expansion reactions [23][24][25][26][27][28]. They have also proved to be precursors for densely functionalized cyclopropanes via ringretaining C-C [29][30][31][32][33][34][35][36][37] and C-heteroatom bond forming reactions to their exocyclic double bond.…”

“…Methylenecyclopropanes are strained, but remarkably stable, unsaturated carbocycles that have attracted significant interest for their strain-driven reactivity. − Typically, these highly strained systems are susceptible to ring-opening reactions, − cycloaddition reactions, − and ring-expansion reactions. − They have also proved to be precursors for densely functionalized cyclopropanes via ring-retaining C–C − and C–heteroatom bond-forming reactions to their exocyclic double bond. − …”