A facile method for the simple synthesis of tetracyclic indoloisoxazolidine frameworks
from Baylis–Hillman derivatives through formation of nitrones in situ followed by
an intramolecular [3+2]-dipolar cycloaddition reaction sequence is described. High
regio- and stereoselectivity, excellent yields, together with the creation of two
rings and three contiguous stereogenic centers including one all carbon quaternary
center, are the salient features of the present method.
Key words
fused-ring systems - indoles - 1,3-dipolar cycloaddition - stereoselectivity - regioselectivity