4- Benzyloxy-l-

E)-2-(4-benzyloxy-l-chloro-2-butenyl)-4.4,5,5-tetramethyl-l, 3,2-dioxaborolane yield 93% 90% isomeric purity... 

The following is an example for a sequential one-pot epoxide formation/nucleophilic opening process using (S)-4-(benzyloxy)-l,2-butanediol, iV-(p-tohienesulfonyl)-imida-zole, and 2-lithio-l,3-dithiane ... 

The metal-catalysed olefin metathesis (equation 122) when applied to dienes results in ring-closure and expulsion of an olefin (equation 123). Thus the molybdenum carbene complex 241 promotes the decomposition of the 1,6-heptadiene derivative 242 to a mixture of the cyclopentene 243 and ethylene (equation 124)122. An analogous reaction of the alcohol 244 gives 245 (equation 125), and 4-benzyloxy-l,7-decadiene (246) affords the cyclohexene 247 and 1-butene (equation 126). These transformations, which occur in benzene at room temperature, proceed in excellent yields122. 

Die leichte Spaltbarkeit von 1,3-Oxazol-Derivaten macht diese zu geeigneten Ausgangs-materialien fur die Synthese von 2-Amino-a kanolen, wie die Herstellung von 3-Amino-4-benzyloxy-l, 2-butandiol-Hydrochlorid bus 4-(Benzyloxy-methyl)-5-hydroxymelhyl-2-tri-chlormethyl-4,5-dihydro-l,3-oxazol zeigt2 ... 

The reaction is prevented in the case of low-lying rot excited states, which are responsible for the lack of photocyclization of azobenzenes and benzylidene anilines. However, when the electronic configuration switches to a low-lying mt excited state upon complexation with Lewis acids, photocyclization takes place under these conditions [30]. Similarly, the presence of perchloric acid allows that, upon irradiation, (E)-4-benzyloxy-l,l,3,4-tetraphenyl-2-azabuta-l,3-diene is transformed in an isoquinoline derivative (Scheme 9.21) [31, 32]. 

Benzyloxy-l-fluoro- E10 (Oxirane + HF/Amin) 4-Benzyloxy-3-fluoro-E10(Oxiran + HF/Amin)... 

An elegant total synthesis of a semi-protected form of lincosamine has been realized by Marshall and Beaudoin [319]. Destomic acid (6-amino-6-deoxy-L- fycero-D- a/acto-heptonic acid) has been derived in a similar way from a L-serinal derivative via hetero-Diels-Alder addition to l-ethoxy-3-[(trimethylsilyl)oxy]-4-benzyloxy-l,3-butadiene. A similar method has been applied also to prepare a semi-protected form of anhydrogalantinic acid, a component of the antibiotic galantin I [351]. 

The Michaelis-Arbuzov reaction has been extended to substituted bromomethyl epoxides such as cis- and tr(7M.v-l,3-diphenyl-2,3-epoxy-4-brorno-l-but monc andcA-4-benzyloxy-l-bromo-23-cpoxybutane 2 to give the substituted diethyl 23-epoxypropylphosphonates in high yields. 

Hydroxy-4-benzyloxy-l-(2-amino-alhyl)-benzol5 11 g 3-Hydroxy-4-benzyloxy-phenylacetonitril werden in 40ml Methanol und 40m/ fliissigem Ammoniak mit 5 g Raney-Kobalt bei 120 bar und 85-90° 5 Stdn. hydriert. Man filtriert vom Katalysator ab, dampft i. Vak. ein und lost den Riickstand in 200 ml lauwarmer 3 n Salzsaure. Man filtriert erneut, dampft i. Vak. ein und kristallisiert den Riickstand aus Athanol/Ather um Ausbeute (//>-drochlorid) 10,8 g (83% d.Th.) F 197-199°. 

Dimethoxy-4-benzyloxy-l-(2-amino-athyl)-aus 3,5-Dimethoxy- 4-benzyloxy-ph enylace-tonitril durch katal. Hydrierung mit Raney-Kobalt 134... 

Alcohol 45 was synthesized by treatment of 4-benzyloxy-l-butane oxide 44 with sodium benzyloxide, then converted to the acetoxymethyl ether 46, which condensed with diacetylguanine to give 47, whose deprotection gave 48 (86JMC1384). It is less active than DHPG against HSV-1. 

Treating 624 with methylene iodide, zinc, and trimethylaluminum in THF provides a good yield of the 4-benzyloxy-l-pentene derivative 672. Hydrogenation of the olefin and simul-... 

Typical procedure. (2S,3S)-4-Benzyloxy-l,2,3-butanetriol 1,2-cyclic carbonate 1152 (Method A) [812] To a stirred solution of triphosgene (104 mg, 0.35 mmol) in di-chloromethane (1 mL) at —70 °C were added pyridine (0.29 mL, 3.59 mmol) and a solution of triol 1151 (125 mg, 0.59 mmol) in dichloromethane (1 mL). Once the addition was complete, the reaction mixture was allowed to warm to room temperature. The resultant homogeneous solution was quenched with saturated aq. ammonium chloride solution, washed with 1 n aq. HCl, saturated aq. NaHCOs, and brine, and dried over anhydrous MgS04. The organic layer was filtered and concentrated in vacuo. The crude product was purified by column chromatography on silica gel using EtOAc/hexanes (1 1) as eluent to afford (2S,3S)-4-benzyloxy-1,2,3-butanetriol 1,2-cyclic carbonate 1152 (108 mg,... 

In some cases, different phosgenation reagents can show different selectivities towards certain substrates. Thus, (2S,3S)-4-benzyloxy-l,2,3-butanetriol reacts with triphosgene in the presence of pyridine to form solely the five-membered external... 

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