INTRAMOLECULAR DIELS-ALDER REACTIONS INVOLVING BORYL-3-PROPENOIC ACID-DERIVATIVES

The coupling of 1,3-dienyl alcohols with boryl-3-propenoic acid 1 or o f 1,3-dienyl secondary amines with the acid chloride 2 leads to the tr ienes 5 and 6 respectively. These are well suited precursors for an in tramolecular Diels-Alder reaction leading to bicyclic cycloadducts hav ing a carbon-boron bond which can be stereoselectively transformed int o a C-O or C-C bond. Thus, the cycloadduct 9 gave the interesting comp ound 10 via a simple oxidation-reduction sequence or the new boronate 11 via a Matteson's homologation. The introduction of chirality at nit rogen or boron in the trienyl amide 6b did not lead to interesting lev els of asymmetric induction. (C) 1998 Published by Elsevier Science Lt d. All rights reserved.