5- Phenyl-4-pentyn

The synthesis of enantiomerically pure propargylic alcohols is possible using the same methodology 43b. Thus, addition of (—)-[(l-chloro-2-phenylethyl)sulfinyl]-4-methylbenzene (14) to propan-al led to a mixture of the diastereomers 15A/15B (d.r. 44 56) which are easily separated by column chromatography. After thermal elimination of the sulfinyl group the vinyl chlorides 16A/16B were obtained as a mixture of E- and Z-oleftns. Elimination of hydrogen chloride was carried out with three equivalents of butyllithium, leading to enantiomerically pure 1 -phenyl-1-pentyn-3-ol. 

Pentyn-1-ol, 33, 68 Peracetic acid, 33, 79 -Phenetidine hydrochloride, 31, 11 a-Phenoxyacetoacetic acid, 33, 44 Phenylacetamide, 32, 92 Phenylacetic acid, 32, 93, 94 33, 70 imino ether hydrochloride, 32, 94 N-Phenylacetimidochloride, 31, 51 Phenylacetonitrile, 30, 44 32, 92 Phenylacetylene, 30, 72 7-Phenylallylsuccinic acid, 31, 85 7-Phenylallylsuccinic anhydride, 31, 86 Phenylazide, 31,16 Phenylazoacetoacetic acid, 32, 85 Phenyl benzoate, 32, 103 IttZtti-l-PHENYL-l,3-BUTADIENE, 30, 75 7-Phenylbutyric acid, 33, 91 a-PHENYL-a-CARBETHOXYGLUTARO-NITRILE, 30, 80, 82 tt-Phenylcinnamonitrile, 32, 63 Phenyldichlorophosphine, 31, 88 0-PhENYLENE CARBONATE, 33, 74 o-Phenylenediamine, 30, 56, 86... 

N-Aryl analogs have been synthesized193 by cycloaddition of terminal-acetylenic sugar derivatives to azides, as exemplified by the conversion of the pentyne derivative 171a into l-phenyl-4-(D-threo-... 

Prepared in 68% overall yield by bromination of 5-phenyl-1-pentyn-3-ol (BuLi and then Br2) followed... 

Two methods for the direct conversion of terminal alkynes to alkynyl(phenyl)iodo-nium tetrafluoroborates have been reported, but their generality has not been documented in the literature. The ter -butylethynyl salt has been prepared by the generation of lithium tert-butylethynyl(trifluoro)borate and its coupling with iodosylbenzene by the standard method (equation 29)80. The treatment of 1-pentyne and phenylacetylene with diphenyl-ju-oxodiiodine(III) bistetrafluoroborate in dichloromethane likewise affords the corresponding alkynyliodonium tetrafluoroborates (equations 30)29. 

The organolithiums derived from either 1-phenyl- or l-(trimethylsilyl)-5-iodo-l-pentyne cyclize at room temperature to give the cyclobutylidene derivatives in excellent yield, without trace of the 5-endo product [13a,b] (Scheme 7-23). 

To an oven-dried reaction vial were added 11 mg Pd(OAc)2 (0.05 mmol), 47 mg l,l -bis(di-f-butylphosphino)ferrocene (0.1 mmol), and 346 mg potassium carbonate (2.5 mmol). The vial was purged with argon. Then 123 jxL 2-chloro-4-methylaniline (1 mmol), 192 xL 1-phenyl-l-pentyne (1.2 mmol), and 2 mL NMP were added via syringe. The reaction was heated to 130°C, stirred at the same temperature and monitored by HPLC. The reaction was complete after 4 h. The ratio of the regioisomer was 91 9. The mixture... 

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