N–O Cleavage reactions of heterobicycloalkene-fused 2-isoxazolines

• Jaipal R. Nagireddy,
• Geoffrey K. Tranmer,
• Emily Carlson and
• William Tam

Beilstein J. Org. Chem. 2014, 10, 2200–2205, doi:10.3762/bjoc.10.227

• yields (66–95%) and without the need for chromatographic purification. Keywords: azabicycloalkene; β-hydroxyketone; 2-isoxazoline; oxabicycloalkene; Raney nickel; Introduction 2-Isoxazolines 1 are practical precursors to countless structural motifs found in nature. Various carbonyl compounds 2, β

Desymmetrization of 7-azabicycloalkenes by tandem olefin metathesis for the preparation of natural product scaffolds

• Wolfgang Maison,
• Marina Büchert and
• Nina Deppermann

Beilstein J. Org. Chem. 2007, 3, No. 48, doi:10.1186/1860-5397-3-48

• following two reasons: 1. Azabicycloalkene 7 is easy to synthesize via Diels-Alder reaction.[62] 2. It was assumed to be a good substrate for RORCM because it is strained and has been shown to be susceptible to other desymmetrizing ring opening reactions in the past.[63][64] To generate appropriate

• isoindole derivative 11 in good yield, verifying our previous assumptions. As a general trend, it turned out that benzannelated azabicycloalkene derivatives like 8 and 10 give relatively unstable products. In consequence, products can only be isolated as pyridones 9, derived from spontaneous aromatization

• desymmetrization of bis-olefin 10 with the known chiral ruthenium catalyst 3.[67] This reaction gave enantioenriched 11 in good yield (Scheme 5). However, the enantioselectivity of this reaction is only moderate compared to similar reactions using molybdenum based precatalysts and different azabicycloalkene