Allenyl allylic ethers: synthesis and thermal rearrangements
摘要:
Application of the sequence halogenation/dehydrohalogenation/isomerization to alkenes 1a-g affords allenyl allylic ethers 5a-g. Thermal isomerizations of 5a,d,e proceed by Claisen rearrangement, while 5b,c,f,g are transformed by alternate modes of [2 + 2]cycloaddition involving biradical intermediates of type 19 to polycyclic structures; the variations in these thermal isomerizations are mainly a function of ring size.
Thermal isomerizations of allenyl cycloalken-3-yl ethers
作者:Jean-Pierre Dulcere、Jack K. Crandall
DOI:10.1039/c39900000561
日期:——
Thermalisomerization of allenylether (1b) proceeds by intramolecular [2 + 2] cycloaddition to give (4), whereas the higher homologue (1c) is transformed by an alternate mode of [2 + 2] cycloaddition to the unstable alkene(7), which spontaneously dimerizes to (8) and (9); X-ray determinations confirm the structures of (8), (9), and lactone (6) derived from (4).
Allenyl ethers as precursors of .alpha.-methylene-.gamma.-butyrolactones and botryodiplodin derivatives
作者:Jean Pierre Dulcere、Mohamed Naceur Mihoubi、Jean Rodriguez
DOI:10.1021/jo00073a033
日期:1993.10
Beta-Bromopropargyl ethers 2a-h, 11, and 12 or allyl propargyl ethers 8d-h are easily isomerized with potassium tert-butoxide (KO-t-Bu) into the corresponding allenyl derivatives 3a-h, 13, 14, and 9d-h. These compounds afford alpha-methylene-gamma-butyrolactones 7a-h, 25, and 26 by application of the sequence halogenation/dehydrohalogenation/homolytic carbocyclization. Starting from methyl vinyl ketone 1i, similar transformations lead to botryodiplodin (27) or ethoxybotryodiplodin (28).
DULCERE, JEAN-PIERRE;CRANDALL, JACK K., J. CHEM. SOC. CHEM. COMMUN.,(1990) N, C. 561-563
作者:DULCERE, JEAN-PIERRE、CRANDALL, JACK K.
DOI:——
日期:——
DULCERE, J. P.;MIHOUBI, M. N.;RODRIGUEZ, J., J. CHEM. SOC. CHEM. COMMUN.,(1988) N 3, 237-239
作者:DULCERE, J. P.、MIHOUBI, M. N.、RODRIGUEZ, J.
DOI:——
日期:——
A new synthetic route to β-bromoprop-2-ynyl mixed acetals and bromovinyl bis-allyl mixed acetals, precursors of α-methylene-γ-butyrolactones
作者:J. P. Dulcere、M. N. Mihoubi、J. Rodriguez
DOI:10.1039/c39880000237
日期:——
in methanol of β-bromoallenyl ethers (3a–g) or allyl allenyl ethers (8d–f) affords unsaturated halogeno-compounds (5a–g) or (9d–f) which are converted via homolytic carbocyclization into α-methylene-γ-butyrolactones (7a–g).