| Abstract
| - The behavior of 1-tosyl-3-acetylindole (1a), N,N-diethyl-1-tosyl-3-indoleglyoxylamide (1b), and1-tosyl-3-nitroindole (1c) as dienophiles in Diels−Alder reactions under thermal and/or high-pressureconditions was explored with different dienes: isoprene (2), 1-(N-acetyl-N-propylamino)-1,3-butadiene (3), and 1-methoxy-3-trimethylsilyloxy-1,3-butadiene (Danishefsky's diene) (4). Comparedto the acylated indoles, the nitro derivative proved to be the best dienophile. In general, the use ofDanishefsky's diene led to high-yielding reactions under milder conditions. Likewise, high-pressureconditions proved to be better in producing high yields of products. The advantage of high-pressureover thermal conditions was the ability of the former to generate highly functionalized adducts inbetter yields, which were otherwise very difficult or impossible to obtain. The use of thermal orhigh-pressure conditions led to different regio- and/or stereoselectivity in the adducts, allowingcontrol of the regio- or stereoisomer produced.
|
