Catalytic Use of Elemental Gallium for Carbon–Carbon Bond Formation
作者:Bo Qin、Uwe Schneider
DOI:10.1021/jacs.6b06767
日期:2016.10.12
The first catalytic use of Ga(0) in organic synthesis has been developed by using a Ag(I) cocatalyst, crownether ligation, and ultrasonic activation. Ga(I)-catalyzed C-C bondformations between allyl or allenyl boronic esters and acetals, ketals, or aminals have proceeded in high yields with essentially complete regio- and chemoselectivity. NMR spectroscopic analyses have revealed novel transient Ga(I)
backbone and the allenyl side chains, Lewis acid-catalyzed three-component condensationreactions of aldehydes, alkoxytrimethylsilanes, and 1-trimethylsilyl-2-butyne were studied. The reaction of these three compounds took place in the presence of a catalytic amount of TrClO4 at −78°C to yield the corresponding α-allenyl ethers in good yields. This reaction was also applied to the synthesis of a polyether
Novel Substituent and Chelating Effects in the Pd-Catalyzed Reaction of 2,3-Allenols, Aryl Iodides, and Amines. Highly Regio- and Stereoselective Synthesis of 2-Amino-3-alken-1-ols or 4-Amino-2(<i>E</i>)-alken-1-ols
作者:PORNET, J.、MIGINIAC, L.、JAWORSKI, K.、RANDRIANOELINA, B.
DOI:——
日期:——
Simultaneous Construction of Polymer Backbone and Side Chains by Three-Component Polycondensation. Synthesis of Polyethers with Allenyl Side Chains from Dialdehydes, Alkylene Bis(trimethylsilyl) Ethers, and Propargyltrimethylsilane
perchlorate (TrClO4) at −50 °C to yield the desired polyethers consisting of 1, 2, and 4b with a molar ratio of 1:1:2 in good yields. This polyether was treated with a cationic catalyst such as BF3OEt2 to give a cross-linked polymer. This polymersynthesis is unusual in that it concurrently constructs both the polymerbackbone and the functionalsidechainsfrom three starting compounds.