Iron salt-catalyzed Friedel-Crafts alkylation of chiral α-aryl alcohols with a trimethylsilyl group was found to proceed with retention of the configuration of the hydroxyl group as a leaving group. The memory of chirality of this system stems from the β-silyl effect of the trimethylsilyl group on the carbocation intermediate.

Abstract-High-resolutionfrequency-modulated continuous-wave (FMCW) reflectometry is realized by using a single-mode vertical-cavity surface-emitting laser (VCSEL) as a frequency-swept light source for the first time. The optical frequency of the VCSEL is swept by the injection current modulation. The experimental spatial resolution of 250 m was achieved, which is the best value when an injection current tuned laser diode is used as a frequency-swept light source.Index Terms-Frequency-modulated continuous-wave (FMCW) reflectometry, optical frequency domain reflectometry (OFDR), reflectometry, vertical-cavity surface-emitting laser (VCSEL).

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Bis-BINOLs 7a-c in which two BINOL units are tethered by phenylenebis(ethynyl) groups react with titanium tetraisopropoxide (2 equiv) to form intramolecular dimeric titanium(IV) aggregates 2a-c. Of these, 2a,b with an o-phenylenebis(ethynyl) tether are stable in the presence of excess titanium tetraisopropoxide. Complex 2a exhibits a relatively high enantioselectivity in asymmetric addition of diethylzinc to an aldehyde. [structure: see text]