Electrochemical reduction of 1,3-diketones in hydroorganic medium. Preparation of 1,2-cyclopropanediols

Abstract

JOSEPH ARMAND and LINE BOULARES. Can. J. Chem. 54, 1197Chem. 54, (1976. The electrochemical reduction of 1,3-diketones C6H5-CO-CRIR2-CO-R3 (R1 = H, CH3; RZ = CH3, CH2C6H5; R3 = CH3, C6H5) in an hydroorganic medium corresponds to a bielectronic process and leads to I,?-cyclopropanediols which, in most cases, are obtained in good yields. The polarographic results are presented and the mechanisms are discussed, JOSEPH ARMAND et LINE BOULARES. Can. J. Chem. 54, 1197 (1976). La r6duction 6lectrochimique des dicetones-1,3, C6H5-CO-CRIR2-CO-R3 (R1 = H, CH3; R2 = CH,, CH2C6H5 ; et R3 = CH,, C6H5), dans un milieu hydroorganique correspond k' un processus bi6Lectronique et conduit aux cyclopropanediols-l,2 qui sont obtenus dans la plupart des cas avec de bons rendements. On prisente les risultats polarographiques et on discute des micanismes.[Traduit par le journal]

Photochemical reaction of 3-hydroxy-1-(o-methylaryl)alkan-1-ones: formation of cyclopropane-1,2-diols and benzocyclobutenols through β- and γ-hydrogen abstractions

“…(5 x Me), 26.6 (d,CHMe,),27.8 (s,, 65.1 (s) and 66.6 (s) (C-1 and -2), 125.4 (d), 127.7 (d), 130.9 (d), 131.4 (d) m,ArH); S , 13.9 (q), 18.4 (q), 19.1 (q), 19.8 (q), 20.4 (9) (5 x Me), 25.9 (s,29.7 (d,CHMe,), 64.4 (s) and 64.8 (s) (C-1 and -2), 125. 3 (d), 127.9 (d), 128.4 (d), 131.2 (d), 136.5 (s) and 140.0 (s) (Arc).…”

Regio- and stereoselective 1,2 Wagner-Meerwein shifts during trifluoroacetic acid catalyzed isomerization of unsymmetrically substituted tricyclo[3.2.0.02,4]heptanes

“…13 In general, the energy demands for stereomutation of the type 26 ^27 fall into the range of 35-40 kcal/mol. However, the presence of 7r-donor substituents at C5 is known to lower somewhat the barrier to ring flip isomerization, as expected from the usual remote cyclopropane bond weakening effects which come into play as the result of antibonding interactions with such groups.14 Bicyclo[2.1 .Ojpentanes are also subject to transition metal promoted isomerization.15-17 With rhodium(I) catalysts in particular, rearrangement to a cyclopentene is believed to result from initial oxidative addition to the strained central bond (see 28), abstraction of the exo-Cs hydrogen to form an allylrhodium hydride of type 29, and decomposition of the latter to MH 29 olefin and metal complex. Normally, Lewis acid catalysts of the Fe(III), Ni(II), Cd(II), Mg(II), Zn(II), Hg(II), and Ag(I) are inactive under comparable conditions.…”

Synthesis of Anhydroryanodol

“…As illustrated in Figure , Ti-mediated annulation of 12 was conducted without oxidative termination to deliver the desired product 19 in 61% yield . Surprisingly, this reaction routinely delivered a mixture of products (∼1.4:1 to ∼1.6:1) containing a minor amount of the undesired cyclopropane 20 , apparently derived from stereoselective reductive cyclization of the 1,3-diketone of 12 .…”