Synthesen in der hydroaromatischen Reihe. III. 1. Weitere Diensynthesen des 1‐Äthinyl‐6‐methoxy‐3,4‐dihydro‐naphtalins und des 1‐Vinyl‐6‐methoxy‐3,4‐dihydro‐naphtalins. 2. Die Kondensation von Cyclopentandionen mit Acetylen

Abstract

Synthesen in der hydroaromatischen Reihe. 111.

The Diels-Alder Diene Synthesis.

“…Barnett (74) reported failure to obtain a pure maleic anhydride addition product with bidialin, and stated that no reaction was observed between bidialin and p-benzoquinone Benzologs of 1 -vinyl-1 -cyclohexene have also been studied. 6-Methoxy-lvinyl-3,4-dihydronaphthalene has been studied extensively, because the products formed are of importance in that they are preliminary products obtained in the rapidly developing field of sterol syntheses by diene reactions (93,129,130,131,132,133). By choice of suitable dienophiles, adducts possessing the sterol-ring structure may be prepared, as shown in table 6.…”

“…The semicyclic enynes, 3,4-dihydro-1-naphthylacetylene and its 6-methoxy derivative, add ethylenic and acetylenic dienophiles; the latter type of dienophile gives derivatives of 9,10-dihydrophenanthrene as adducts. Propiolic acid (130) gives a mixture of 9,10-dihydrophenanthrene-1 -and 2-carboxylic acids on reac- interaction occurs (130) in which the quinone is reduced to hydroquinone and XXXII is converted into the anhydride of phenanthrene-1,2-dicarboxylic acid.…”

Ab + D → Abcd

“…The diene 1 has been condensed with numerous other dienophiles [15][16][17][18][19][20][21][22][23][24][25]29], as has 16 [26][27][28]30]. A wide variety of dienes has been utilized, many of them by a Russian group associated with I. N. Nazarov.…”