3- Chloro-2-pentanol

Figure 2.19 shows three stereochemical representations for (2S,3S)-2-chloro-3-pentanol (40). One can interconvert these representations by imagining the view to be had from various perspectives. For example, viewing 40a from the perspective indicated by the eye would produce the bold/ dashed wedge figure 40b, which is properly oriented (substituents on a horizontal line project toward the viewer) to simply draw the Fischer projection, 40c. Note that a Fischer projection shows an eclipsed conformation of the structure, so ordinarily it does not represent the most stable conformation. 

Finally, reaction of primary, secondary, or tertiary alcohols 11 with Me3SiCl 14 in the presence of equivalent amounts of DMSO leads via 789 and 790 to the chloro compounds 791 [13]. n-Pentanol, benzyl alcohol, yS-phenylefhanol or tert-butanol are readily converted, after 10 min reaction time, into their chloro compounds, in 89-95% yield, yet cyclohexanol affords after reflux for 4 h cyclohexyl chloride 784 in only 6% yield [13] (Scheme 6.5). 1,4-Butanediol is cyclized to tetrahydrofuran (THF) [13a], whereas other primary alcohols are converted in 90-95% yield into formaldehyde acetals on heating with TCS 14 and DMSO in benzene [13b] (cf also the preparation of formaldehyde di(n-butyl)acetal 1280 in Section 8.2.1). 

Pentanol, 52, 22 trans-2-Pentenal, 4-hydroxy-4-methyl-, 54, 27 Pent-l-en-3-ol, 52, 22 trans-3-PENTEN-2-ONE, 51, 115 PERBENZOIC ACID, m-CHLORO-,... 

Problem 5.14 Write structural formulas for the following, indicating enantiomers, if any. and their configurations (a) 3-methyl-3-pentanol, (ft) 2.2-dimethyl-3-bromohexane. (c) 3-phenyl-3-chloro-l-propene. ... 

Marmor and Maroski2 investigated the reaction of four hindered alkenes with IIOCI in acetone-water (homogenous conditions), but the reaction led to a chlorohydrin in only one case l-chloro-2,4,4-trimcthyl-2-pentanol (34% yield). The products in general are vinyl chlorides. 

Ethyl-3-pentanol Hydrogen 3-Chloro-3-ethylpentane Water... 

Draw the structures of the following compounds (a) 3-ethyl-4-methyl-2-hexanone (b) 2-chloro-buytl acetate (c) ethylbenzene id) 3-ethylcyclohexene (e) 2-methyl-3-pentanol (/) 2-methylpropyl methyl ether. 

C6H15NO 2-amino-4-methyl-1-pentanol, ( ) 16369-17-8 13 00 0.9173 1 9517 C7H3CIN206 2-chloro-3,5-dinitrobenzolc acid 2497-91-8 25.00 1.7473 2... 

C9H20O 3,3,4,4-tetramethyl-2-pentanol 66793-88-2 24.67 0.8302 2 18541 C10H6CI2N2O2 3-chloro-4-(3-chloro-2-nitrophenyl)pyrrole 1018-71-9 25.00 1.4985 2... 

Halomercaptans are converted to thietanes by treatment with a as exemplified by the formation of 3-hydroxythietane 21 from 3-chloro-l-mercapto-2-propanol 20 4-thiocyano-2-pentanol 22 is converted to a mixture of cis- and trans-2,4-dimethylthietane 23 by treatment with sodium hydride. The latter reaction involves displacement of cyanate ion by the mercaptide ion. 2,2,4-Trimethylthietane was also prepared by this method. 

The 4,10,16-triaza-18-crown-6 macrocycle shown above was first prepared by Lehn and coworkers (Graf and Lehn, 1975 Lehn, 1985) and was an important intermediate for the synthesis of the first macrotetracyclic polyethers (Canceill et al., 1982 Kotzyba-Hibert et al., 1981 Pratt et al., 1988). The key step in this synthesis was conversion of A-tosyldiethanolamine [TsN(CH2CH20H)2] into the diacid dichloride, TsN(CH2CH20CH2C0Cl)2. As shown above, this conversion was accomplished by reaction with chlo-roacetic acid followed by oxalyl chloride (method A) (Miller et al., 1989) or by chloromethylation, sodium cyanide, hydrolysis and conversion of the diacid to the diacid dichloride (method B) (Graf and Lehn, 1981). The third hypothetical method to the diacid dichloride shown above starts with tosylamide and 5-chloro-3-oxa-l-pentanol followed by Jones oxidation and thionyl chloride (method C) (Qian et al., 1990). 

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