The enantiomeric scaffold approach to highly functionalized 1-oxadecalines: enantio- and regiocontrolled [4 + 2] cycloadditions of 5-alkenyl-eta3-pyranylmolybdenum complexes.
TpMo(CO)2(5-alkenyl-eta-2,3,4-pyranyl) diene complexes function as excellent chiral scaffolds for the efficient regio- and enantiocontrolled synthesis of highly functionalized 1-oxadecaline derivatives through a novel transition metal-mediated Diels-Alder reaction. Very good to excellent yields and excellent levels of endo selectivity are obtained, and the reaction gives products with complete retention of enantiomeric purity when carried out with chiral, nonracemic scaffolds. A subtle structural modification on the diene (replacement of an H by a trans-CH3 group) leads to a complete change of regiochemistry, which is discussed from a mechanistic point of view. The role of the eta3-coordinated TpMo(CO)2 moiety is also critical to the further functionalization of the [4 + 2] cycloadducts, as illustrated by the preparation of 20 variously functionalized 1-oxadecaline derivatives (>98% ee when carried out with high enantiopurity scaffolds).
Arrayás
Ramón Gómez
RG
Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
Yin
Jingjun
J
Liebeskind
Lanny S
LS
D000475:Alkenes / Q000737:chemistry*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis*; D002839:Chromans / Q000138:chemical synthesis*; D003500:Cyclization; D008982:Molybdenum / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011714:Pyrans / Q000737:chemistry*; D013237:Stereoisomerism
D000475:Alkenes; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002839:Chromans; D009942:Organometallic Compounds; D011714:Pyrans; D008982:Molybdenum