Incorporation of an allene unit into alpha-pinene via beta-elimination

Kilbas, Benan
Azizoglu, Akin
Balcı, Metin
The two double-bond isomers 3-iodo-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene (6b) and 3-iodo-4,6,6-trimethylbicyclo[3.1.1]hept-2-ene (11) were synthesized by reacting 2,6,6-trimethylbicyclo[3.1.1]heptan-3-one (9) with hydrazine, followed by treatment with 12 in the presence of Et3N. Treatment of 11 with t-BuOK as base in diglyme at 220 degrees resulted in the formation of 9 and 6,6-dimethyl-4-methylidene-bicyclo[3.1.1]hept-2-ene (12). For the formation of 9, the cyclic allene 7 is proposed as an intermediate. Treatment of the second isomer, 6b, with t-BuOK at 170 degrees gave rise to the diene 12 and the dimerization product 17. The underlying mechanism of this transformation is discussed. On the basis of density-functional-theory (DFT) calculations on the allene 7 and the alkyne 15, the formation of the latter as the intermediate was excluded.


Novel enantioselective synthesis of both enantiomers of furan-2-yl Amines and amino acids
Demir, Ayhan Sıtkı; Sesemoglu, O; Ulku, D; Arici, C (Wiley, 2003-01-01)
A new enantioselective synthesis of furan-2-yl amines and amino acids is described, in which the key step is the oxazaborolidine-catalyzed enantioselective reduction of O-benzyl (E)- and (Z)-furan-2-yl ketone oximes to the corresponding chiral amines. The chirality of the furan-2-yl amines is fully controlled by the appropriate choice of the geometrical isomer of the O-benzyl oxime. Oxidation of the furan ring furnished amino acids in high yields.
Chemistry of the benzotropone endoperoxides and their conversion into tropolone derivatives: Unusual endoperoxide rearrangements
Guney, M; Dastan, A; Balcı, Metin (Wiley, 2005-01-01)
The chemistry of two bicyclic endoperoxides, obtained by photooxygenation of 2,3-benzotropone (= 5H-benzocyclohepten-5-one 5) and of its ethyl carboxylate derivative 15, was investigated with the aim of synthesizing the respective benzotropolone derivatives. The reaction of the endoperoxide 10 derived from 5 with thiourea gave the desired benzotropolone, i.e., 6-hvdroxy-5H-benzocyclohepten-5-one (11), in high yield (Scheme 1). On the other hand, the endoperoxide 16 derived from the ethyl carboxylate derivat...
The first enzymatic resolution of quaternary alpha '-acetoxy alpha,beta-unsaturated cyclohexenones and cyclopentenones
Tanyeli, Cihangir; Iyigun, CEM (Elsevier BV, 2005-12-12)
The enantio selective resolution of various quaternary alpha'-acetoxy alpha,beta-unsaturated cyclohexenones and cyclopentenones was performed with the commercially available enzyme CCL in pH = 8.0 phosphate buffer. Various parameters that would affect the enantioselectivities were tested and the best enzymatic resolution conditions were found to afford the enantiomerically enriched quaternary acetoxylated substrates with high ee varying between 36% and 99%.
Synthesis, characterization, crystal and molecular structure of 1,5-Dihydro-2H-cyclopenta[1,2-b : 5,4-b ']dipyridin-2-imine
Baysal, Akin; Durap, Feyyaz; Gumgum, Bahattin; Yildirim, Leyla T.; Ulku, Dincer; Boga, Ayse Dilek; Özkar, Saim (Wiley, 2007-01-01)
The reaction of 1,5-diliydro-2H-cyclopenta[1,2-b:5,4-b'ldipyridin-2-one (3) with an alkylamine (butvlamine, hexylamine or ethylenediamine) yields, quite unexpectedly and in the absence of catalyst, the novel compound 1,5-dihydro-2H-cyclopentafl,2-b:5.4-b']dipyridin-2-imine (4) as the sole, analytically pure, solid product, which was fully characterized. The structure of 4 was unequivocally solved by single-crystal X-ray-diffraction analysis. The compound crystallizes in a monoclinic cell (space group P 2(1/...
Amination/annulation of chlorobutenones with chiral amine compounds: synthesis of 1,2,4-trisubstituted pyrroles
Demir, Ayhan Sıtkı; Igdir, AC; Gunay, NB (Elsevier BV, 2005-10-03)
A series of 1,2,4-trisubstituted pyrroles have been synthesized in 83-96% yields on treatment of chiral primary amines, amino alcohols and esters of alpha-amino acids with different chlorobutenones in benzene-triethylamine. The conversions proceed without racemization.
Citation Formats
B. Kilbas, A. Azizoglu, and M. Balcı, “Incorporation of an allene unit into alpha-pinene via beta-elimination,” HELVETICA CHIMICA ACTA, pp. 1449–1456, 2006, Accessed: 00, 2020. [Online]. Available: