title: Lipase-catalyzed domino kinetic resolution/intramolecular Diels-Alder reaction: one-pot synthesis of optically active 7-oxabicyclo[2.2.1]heptenes from furfuryl alcohols and beta-substituted acrylic acids.
abstract: The first lipase-catalyzed domino reaction is described in which the acyl moiety formed during the enzymatic kinetic resolution of furfuryl alcohols (+/-)-3 with a 1-ethoxyvinyl ester 2 was utilized as a part of the constituent structure for the subsequent Diels-Alder reaction. The preparation of ester 2 from carboxylic acid 1 and the subsequent domino reaction were carried out in a one-pot reaction. Therefore, this procedure provides a convenient preparation of the optically active 7-oxabicyclo[2.2.1]heptene derivatives 5, which has five chiral, non-racemic carbon centers, from achiral 1 and racemic 3. The overall efficiency of this process was dependent on the substituent at the C-3 position of 3, and the use of the 3-methylfurfuryl derivatives, (+/-)-3 b and (+/-)-3 f, exclusively produced diastereoselectivity with excellent enantioselectivity to give (2R)-syn-5 (91->/=99 % ee) and (S)-3 (96->/=99 % ee). Similar procedures starting from the 3-bromofurfuryl alcohols (+/-)-3 h-j provided the cycloadducts (2R)-syn-5 j-q (93->/=99 % ee), in which the bromo group was utilized for the installation of bulky substituents to the 7-oxabicycloheptene core.
authors.affiliation: Graduate School of Pharmaceutical Sciences Osaka University 1-6, Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Akai
authors.forename: Tadaatsu
authors.initials: T
authors.lastname: Naka
authors.forename: Sohei
authors.initials: S
authors.lastname: Omura
authors.forename: Kouichi
authors.initials: K
authors.lastname: Tanimoto
authors.forename: Masashi
authors.initials: M
authors.lastname: Imanishi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Takebe
authors.forename: Masato
authors.initials: M
authors.lastname: Matsugi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kita
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D004952:Esters / Q000737:chemistry; D005663:Furans / Q000737:chemistry*; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology; D013237:Stereoisomerism
chemical_list: D000179:Acrylates; D001643:Bridged Bicyclo Compounds; D004952:Esters; D005663:Furans; C012986:furfuryl alcohol; D008049:Lipase; C036658:acrylic acid