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Synthesis of allenes by nucleophilic 1,3-substitution
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Reactions
1,3-Substitution with carbon nucleophiles
Recent Literature
A chemoselective isomerization of secondary-type propargylic alcohols under
Appel-type reaction conditions in the presence of Ph3P, CBr4
and additives gives allenic bromides, propargylic bromides and brominated
dienes.
N. Sakai, T. Maruyama, T. Konakahara, Synlett, 2009,
2105-2106.
With a suitable combination of N-heterocyclic carbene precatalyst, base, and
fluorine reagent, a fluorination of alkynals proceeded smoothly to yield a wide
range of α-fluoroallenoates with excellent chemoselectivity. α-Fluorinated
allenoates are versatile synthetic intermediates toward other useful
fluorine-containing building blocks.
X. Wang, Z. Wu, J. Wang, Org. Lett., 2016, 18,
576-579.
A copper-catalyzed synthesis of benzyl-, allyl-, and allenyl-boronates from
benzylic, allylic, and propargylic alcohols, respectively, exhibits a broad
reaction scope and high efficiency under mild conditions. Preliminarily
mechanistic studies suggest that nucleophilic substitution is involved in this
reaction.
L. Mao, K. J. Szabó, T. B. Marder, Org. Lett.,
2017, 19, 1204-1207.
Bimetallic Pd/Cu and Pd/Ag catalytic systems enable a stererospecifically
borylation of propargylic alcohol derivatives via formal SN2′
pathways to give allenyl boronates. Opening of propargyl epoxides leads to
1,2-diborylated butadienes probably via en allenylboronate intermediate.
T. S. N. Zhao, Y. Yang, T. Lessing, K. J. Szabo, J. Am. Chem. Soc., 2014,
136, 7359-7542.
Gold nanoparticles supported on ZrO2 efficiently generate alkyl
radicals via homolysis of unactivated C(sp3)-O bonds. A subsequent
C(sp3)-Si bond formation provides diverse organosilicon compounds. A
wide array of esters and ethers participated in the heterogeneous gold-catalyzed
silylation by disilanes to give diverse alkyl-, allyl-, benzyl-, and allenyl
silanes in high yields.
H. Miura, M. Doi, Y. Yasui, Y. Masaki, H. Nishio, T. Shishido, J. Am. Chem. Soc.,
2023, 145, 4613-4625.
The silicon nucleophile generated by copper(I)-catalyzed Si-B bond activation
allows several γ-selective propargylic substitutions. Chloride as a leaving
groups is superior in linear substrates, and the phosphate group produces superb
γ-selectivity in α-branched propargylic systems, and enantioenriched substrates
react with excellent central-to-axial chirality transfer.
D. J. Vyas, C. K. Hazra, M. Oestreich, Org. Lett., 2011,
13, 4462-4465.
A Rh-catalyzed coupling reaction between propargylic carbonates and a
silylboronate affords allenylsilanes in high yields. The reaction tolerates
various functional groups and proceeds with excellent chirality transfer.
H. Ohmiya, H. Ito, M. Sawamura, Org. Lett., 2009,
11, 5618-5620.
A Cu(O-t-Bu)-Xantphos catalyst system was effective for the preparation
of various allenylboronates with different substitution patterns, those with
functional groups, and an axially chiral one. A Lewis acid promoted
stereoselective addition of allenylboronates to aldehydes leads to
homopropargylic alcohols.
H. Ito, Y. Sasaki, M. Sawamura, J. Am. Chem. Soc., 2008,
130, 15774-15775.
A copper-catalyzed borylation of propargyl dichlorides provides
chloro-substituted allenyl-Bdan products in very good yields under mild reaction
conditions. Derivatizations of the allenyl-Bdan products are also demontrated.
K.-F. Wu, D.-T. Dai, X.-Y. Sun, Y.-H. Xu, Org. Lett.,
2022, 24, 2660-2664.
A direct and convenient coupling of propargylic substrates with
diphenylphosphine oxide in the presence of Tf2O and 2,6-lutidine
provides attractive allenylphosphoryl skeletons with high atom and step economy
under metal free conditions.
C.-H. Yang, H. Fan, H. Li, S. Hou, X. Sun, D. Luo, Y. Zhang, Z. Yang, J.
Chang,
Org. Lett., 2019, 21, 9438-9441.
A facile and efficient copper-catalyzed direct C-P cross-coupling of unprotected
propargylic alcohols with P(O)H compounds provides valuable allenylphosphoryl
frameworks with operational simplicity and high step- and atom-economy under
ligand-, base-, and additive-free conditions.
G. Hu, C. Shan, W. Chen, P. Xu, Y. Gao, Y. Zhao, Org. Lett.,
2016, 18, 6066-6069.
A new, efficient method based on a palladium(0)-catalyzed reaction of
propargylic derivatives with various phosphorus nucleophiles produces
allenylphosphonates and their analogues with defined stereochemistry in the
allenic and the phosphonate moiety.
M. Kalek, T. Johansson, M. Jezowska, J. Stawinski, Org. Lett., 2010,
12, 4702-4704.
A regio- and chemoselective sulfonylation of propargyl alcohols with
sulfinamides in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) provides
straightforward and mild access to multi-substituted allenyl sulfones. This
transformation was promoted by HFIP and did not require any catalysts or
oxidants.
F.-F. Zou, Z. Luo, Y.-T. Yang, X. Zhuang, C.-M. Hong, Z.-Q. Liu, W.-F. Li,
Q.-H. Li, T.-L. Liu, J. Org. Chem., 2022, 87,
15061-15070.
A TBHP/TBAI-mediated reaction of propargyl alcohols with sulfonyl hydrazides in
the presence of HOAc provides allenyl sulfones in good yields in a short
reaction time via HOAc-promoted sulfonohydrazide intermediate formation,
sequential C-O, C-N, and N-S bond cleavage, and C-S bond formation. This
reaction shows highly functional group compatibility and excellent
regioselectivity.
Z. Yang, W.-J. Hao, S.-L. Wang, J.-P. Zhang, B. Jiang, G. Li, S.-J. Tu, J. Org. Chem.,
2015,
80, 9224-9230.