Propargylation of carbonyl compounds: An efficient method for the synthesis of homopropargyl alcohols
作者:Jorge A. Cabezas、Leonardo X. Alvarez
DOI:10.1016/s0040-4039(98)00727-8
日期:1998.6
Controlled dilithiation of allene, with two equivalents of n-butyllithium, produces the propargyl dianion 5. The latter couples efficiently with carbonyl compounds to produce homopropargyl alcohols in high yields.
Efficient Propargylation of Aldehydes and Ketones Catalyzed by Titanocene(III)
作者:José Justicia、Iris Sancho-Sanz、Enrique Álvarez-Manzaneda、J. Enrique Oltra、Juan M. Cuerva
DOI:10.1002/adsc.200900479
日期:2009.10
We describe a novel method for the propargylation of a wide range of aldehydes and ketonescatalyzed by titanocene(III) complexes under mild reaction conditions and compatible with many functional groups. Homopropargylic alcohols are obtained as the sole products even when ketones are used as starting materials, which is unusual in Barbier-type propargylations.
A new method for the preparation of 1,3-dilithiopropyne: an efficient synthesis of homopropargyl alcohols
作者:Jorge A Cabezas、Albán R Pereira、Adam Amey
DOI:10.1016/s0040-4039(01)01429-0
日期:2001.9
propargyl bromide with two equivalents of n-butyllithium, in the presence of TMEDA, produces the operational equivalent of the dianion 1,3-dilithiopropyne. The latter reacts efficiently with aldehydes and ketones to produce homopropargyl alcohols in a single step route and in high yields.
The Prevalence of Daytime Napping and Its Relationship to Nighttime Sleep
作者:June J. Pilcher、Kristin R. Michalowski、Renee D. Carrigan
DOI:10.1080/08964280109595773
日期:2001.1
Many healthy adults report daytime napping. Surprisingly few studies, however have examined spontaneous napping behavior especially very short naps, in healthy adults. The authors examined the prevalence of power naps (lasting less than 20 minutes) and longer naps (20 minutes or more) and their effects on nighttime sleep in a group of healthy young and middle-aged adults. The young and middle-aged adults reported very similar sleep and napping patterns, with approximately 74% of the participants in both groups reporting they had napped during a 7-day sleep-log period. Almost half of the participants reported that the average nap lasted less than 20 minutes. A multivariant analysis of variance (MANOVA) found no significant differences between the no-nap and the power-nap or long-nap groups in sleep quantity or quality for either age group. The current data suggested that power napping occurs frequently in healthy adults and that spontaneous napping does not negatively affect nighttime sleep.