Access to polyfunctionalized diquinanes, hydrindanes, and decalines via TiCl4 promoted Michael-aldol and Baylis-Hillman reactions.

The addition of 0.5 equiv of TiCl(4) to (cyclo)alkanones tethered to α,β-unsaturated ketones afforded polyfunctionalized diquinanes, hydrindanes, and decalines. These products, resulting from a Michael-aldol or a Baylis-Hillman reaction, can be obtained with high or total diastereoselectivity in moderate to high yields. These scaffolds represent interesting building blocks for the synthesis of complex natural products.