TOTAL SYNTHESIS OF (+)-MONOMORINE-I VIA NITRONE CYCLOADDITION ROUTE

An enantioselective total synthesis of (+)-monomorine I (1) is described. The key feature of the synthesis is the asymmetric 1,3-dipolar cycloaddition of the prochiral nitrone 9 with the chiral (S)-allylic ether 8 as a dipolarophile, which provides stereoselectively the C-3,C-5-trans-isoxazolidine 10 with the correct relative and absolute stereochemistry suitable for the synthesis of (+)-monomorine I.