Asymmetric synthesis of trans -4,5-disubstituted γ-butyrolactones involving a key allylboration step. First access to (−)-nicotlactone B and (−)-galbacin

HENRION, S.; MACÉ, A.; VALLEJOS, M. M.; ROISNEL, T.; CARBONI, B.; VILLALGORDO, J. M.; CARREAUX, F.

ORGANIC & BIOMOLECULAR CHEMISTRY

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2018 vol. 16 p. 1672 - 1678

1477-0520

An efficient asymmetric synthesis of trans-4,5-disubstituted γ-butyrolactones from aldehydes and enantioenriched γ-carbamate alkenylboronates is reported. The cornerstone of this strategy is the implementation of sequential [3,3]-allyl cyanate rearrangement/allylboration/nucleophilic addition/cyclisation reactions. Diverse γ-butyrolactones such as the flavouring compounds, (+)-trans-whiskey lactone and (+)-trans-cognac lactone, as well as an advanced intermediate towards the first synthesis of natural products, (−)-nicotlactone B and (−)-galbacin, have thus been obtained.