“…11 It is worth noting that generally 1,3-DCA of (1) with substrates of type (4) takes place with lower selectivity than the corresponding Diels-Alder reactions, 11,12 and Lewis acids retard the 1,3-DCA and decrease yields with no improvement in diastereoselectivity. Higher diastereoselectivity (80-90% de) is observed if bornyl crotonates, 13 chiral imides, 14 alkenes containing a chiral imidazolidine controller, 15 or carbohydrates 16 Acryloylsultams such as (5) 17a and (S)-and (R)-(6) 17b are the best auxiliaries for almost complete asymmetric induction yielding, after reduction, enantiomerically pure isoxazolines (eq 7). Because the 2 -isoxazoline ring can be readily cleaved, this chemistry provides a powerful approach to the synthesis of polyfunctional compounds from alkenes.…”