Total Synthesis of Elaiolide Using a Copper(I)-Promoted Stille Cyclodimerization Reaction
摘要:
The 16-membered macrodiolide elaiolide (2) has been prepared in 20 steps from the ketone (S)-8 in 9.3% overall yield with a diastereoselectivity of 76%, Key steps included the copper(I) thiophene-2-carboxylate promoted cyclodimerization of the vinyl stannane 3 to give the C-2-symmetric macrocycle 16 in 80% yield and the two directional aldol coupling of the macrocyclic diketone 17 with aldehyde 5. Most of the stereocenters in the macrocyclic precursor 3 were constructed using boron aldol methodology developed in this laboratory.
Synthesis of the C(7)-C(20) Fragment of Spirotoamides A, B and C
作者:Allan Rossini、Luiz Dias
DOI:10.21577/0103-5053.20190126
日期:——
This work describes the preparation of the C(7)-C(20) fragment of spirotoamides A to C in a very elegant fashion, achievement very high levels of stereocontrol. The synthesis has been accomplished by a sequence involving 14 steps (0.36% overall yield, average of 81% for each step) in high diastereo and enantioselectivity, employing, as determining steps, asymmetric Mukaiyama and boron-mediated 1,5-anti promoted aldol reactions between alpha-methyl-beta-hydroxyketones and aldehydes.