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The title nanobelts are synthesized by chemical vapor transport reaction of Hf and S powders (quartz tube, 650 °C, temperature gradient about 10 K/cm, 5 h).

Title compound (II), key building block for the synthesis of the first-in-class Janas tyrosine kinase inhibitor CP-690,550, is prepared from cheap raw materials using established transformations.

Carbocations derived from crude furan aldehydes are trapped by the formyl function to give the novel title compounds directly.

The chemoselective reduction of one double bond of various electron-rich dienes, e.g. (I), (III), (V) and (XI) is smoothly achieved in the system NaBH4—NiCl2—MeOH.

The key step involves an intramolecular Friedel—Crafts reaction of the tethered electron-rich anilide with the oxocarbenium derived from the furan ring.

Two acid-catalyzed conversions of furandiols 8 and its dehydration spiroacetalized products 9 into oxabicyclic cyclopentenones 10 in good to excellent yields are reported. To disclose the mechanism of these conversions, the fact that H2O catalyzes the conversion of 9 into 10 is presented and intermediates 9k and 20i have been structurally verified. In addition, two other related conversions of spiroacetal enol ethers 11 and 14 derived from 8 into cyclopentenones are presented, for which an intramolecular aldol reaction is the key step. On the basis of these results, we propose that these conversions occur through an aldol condensation step instead of electrocyclization of the 4 pi-electron system, which was previously reported. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)