ChemInform Abstract: Highly Stereoselective Titanium‐Mediated Aldol Reactions from Chiral α‐Silyloxy Ketones. A Reliable Tool for the Synthesis of Natural Products.

Abstract

Highly Stereoselective Titanium-Mediated Aldol Reactions from Chiral α-Silyloxy Ketones. A Reliable Tool for the Synthesis of Natural Products. -The influence of substitution pattern of α-siloxy ketones on the reactivity in Ti-mediated aldol reactions is studied. The reaction affords syn,syn-products with excellent diastereoselectivity, irrespective of the substituents applied. Further manipulation of the initial aldol adducts is studied, including removal of the original stereocenter [cf. (V)] and stereoselective reduction of the carbonyl group [cf. (XI)]. A variety of polyol derivatives can be achieved, which represent key subunits of natural or bioactive products [cf. NFX-2 (IX), antimycinone or salinomycin]. -(ESTEVE, J.; JIMENEZ, C.; NEBOT, J.; VELASCO, J.; ROMEA*, P.; URPI, F.; Tetrahedron 67 (2011) 33, 6045-6056, http://dx.