Efficient one-step synthesis of trialkylsubstituted 2(5H)-furanones utilizing direct Ti-crossed aldol condensation and its application to the straightforward synthesis of (R)-mintlactone and (R)-menthofuranElectronic supplementary information (ESI) available: calculated structures of 7 and 8. See http://www.rsc.org/suppdata/cc/b2/b208077j/
TiCl4–Bu3N-mediated condensation of ketones with α,α-dimethoxyketones afforded trialkylsubstituted 2(5H)-furanones in a one-pot manner, wherein aldol addition and furanone formation occurred sequentially; its application to straightforward synthesis of (R)-mintlactone and (R)-menthofuran, two representative natural mint perfumes, is demonstrated.
The formation of a nickeladihydrofuran by oxidative cyclization of an alkyne and an aldehyde with nickel(0) has been demonstrated; the transformation of the nickeladihydrofuran into an enone by decomposition, a lactone by carbonylation and an allylic alcohol by treatment with ZnMe2 suggests that nickeladihydrofuran is an important key intermediate in a variety of catalytic reactions.