The readily accessible 2-halogeno-1-trimethylsilyloxy-1,3-butadienes react smoothly with dimethyl acetylenedicarboxylate to afford 4-halophthalic esters. One of these cycloadducts was subsequently converted into heterocyclic analogues of phantolide like musk fragrances.
The readily accessible 2-halogeno-1-trimethylsilyloxy-1,3-butadienes react smoothly with dimethyl acetylenedicarboxylate to afford 4-halophthalic esters. One of these cycloadducts was subsequently converted into heterocyclic analogues of phantolide like musk fragrances.
The rate retarding effect of alkyl groups on arene metalation quantified
作者:Eckhard Baston、Qian Wang、Manfred Schlosser
DOI:10.1016/s0040-4039(99)02160-7
日期:2000.1
tert-alkyl substituent effects on the metalation rates at aromatic ortho, meta and para positions. Unlike alkyl groups, hetero elements generally accelerate metalationreactions. 1,1,3,3-Tetramethyl-1,3-dihydroisobenzofuran undergoes the hydrogen/metal exchange 3–6 times faster than the indanes mentioned above, the reaction occurring at both the 5- and at the 4-position.