text: A rather intuitive route to cyclic isomers is the intramolecular conjugate addition to α,β–unsaturated carbonyls (intramolecular Michael addition or IMA). Competent Michael acceptors include conjugated enones, enals or nitroalkene derivatives and examples of other acceptors are sparse.  Despite IMA reactions being ubiquitous in synthesis, very few examples of asymmetric IMA transformations exist.
  Thiourea catalysts with pendant chiral backbones have shown to activate systems with tethered nitroalkane and ester motifs to induce asymmetric IMA. The utility of this transformation was demonstrated in the synthesis of cyclic γ– amino acid precursors (figure 1). It is proposed that activation occurs via H–bonding of both the nitronate and the ester to the thiourea catalyst and explains the interesting selectivity for the E–ester.
  A functional stereodivergent organocatalyzed IMA/lactonization transformation in the synthesis of substituted dihydrofurans and tetrahydrofurans has been studied for its ability to construct important structural motifs in numerous natural products (figure 2).  When ethers such as 3 are subject to (S)–(–)–tetramisole hydrochloride (4) catalyst the result is the syn–2,3–substituted THF while the complementary anti–product is easily accessible via a Cinchona alkaloid catalyst such as 7.