P-methoxybenzyl vinyl ether

The behavior of the 3 -pyridyl-, 3 -indolyl- and 2 -pyrrolyl-substituted j8-nitro-ethenes (31a-c) in the domino cycloaddition was also studied [23]. At 15 kbar, 18 h and RT, the / -nitroethenes (31a-c) reacted efficiently with p-methoxybenzyl vinyl ether (14) and methyl acrylate to form the bicyclic nitronates (32a-c) (Scheme... 

Vinyl acetate (36) and phenyl vinylsulphone (38) reacted as neutral- and electron-poor dipolarophiles respectively, with nitronate (16b) to produce nitroso acetals 37 and 39 (15 kbar, RT, 18 h, Scheme 9.13). In the three-component reaction of the sUyl-protected allyl alcohol (40) (neutral alkene) with p-methoxybenzyl vinyl ether... 

Variation of pressure and solvent can be an additional tool to increase structural diversity as will be shown in the example below. The reaction of p-methoxybenzyl vinyl ether (14) with 3-[( )-2-nitro-l-ethenyl] pyridine (31a) at a pressure of 15 kbar in chloroform yielded the domino adducts 59a and 59b (Scheme 9.21), in accordance with the observations described in Scheme 9.15. NitroaUcene 31a reacted as... 

Kuster GJT, Steeghs RHJ, Scheeren HW. Novel five/five-and six/five-membered bicyclic nitroso acetals from high-pressure-promoted cyclisation reactions of p-methoxybenzyl vinyl ether, l-nitro-2-heteroaryl ethenes, and mono- and di-substituted olefins. Eur. J. Org. Chem. 2001 553-560. 

The C16-C24 ketone fragment 11 was prepared from the homoallylic alcohol 2. After protection of 2 as a p-methoxybenzyl (PMB) ether [24], the oxidative cleavage led to an intermediate aldehyde which was converted to the cis vinyl iodide 9 by using the... 

For the synthesis of the non-diene analogue 65, which bears a benzyl group in the terminal position (Scheme 17), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) cleavage of the p-methoxybenzyl (PMB) ether at the C15-position did not proceed in the presence of the benzyl moiety (oxidation of the methylene in allylic-benzylic-position in C23-position). Therefore, we inverted the order of the first two steps (1) DDQ deprotection on 44 and (2) nickel-catalyzed cross-coupling reaction performed on a free primary alcohol in C15 position. After this minor modification, completion of the synthesis followed the established route Suzuki-Miyaura crosscoupling reaction between alkyl iodide 73 (via its trialkylboronate species) and vinyl iodide 60 to yield 74 selective carbamate installation and final deprotection to afford DDM analogue 65. 

Related Reagents. Benzyl Chloromethyl Ether 2-Chloro-ethyl Chloromethyl Ether Chloromethyl Methyl Ether Dimethoxymethane Ethyl Vinyl Ether p-Methoxybenzyl... 

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