310883-86-4

Upstream product

• 296785-14-3 (6R)-4-methoxy-6-(benzyloxymethyl)-5,6-dihydro-2H-pyran-2-one 
• 153255-54-0 (4R,6R)-6-Benzyloxymethyl-4-hydroxy-tetrahydro-pyran-2-one 
• 147849-63-6 tert-butyl (5R)-3-oxo-5-hydroxy-6-benzyloxyhexanoate 
• 215876-09-8 (3R,5R)-6-benzyloxy-3,5-dihydroxy-hexanoic acid tert-butyl ester 
• 296785-16-5 (4R,6R)-6-(benzyloxymethyl)-4-methoxy-tetrahydro-2H-pyran-2-one 
• 570389-10-5 (R)-6-Benzyloxymethyl-dihydro-pyran-2,4-dione 
• 570389-08-1 (R)-(3-benzyloxy-2-hydroxypropyl)-2,2-dimethyl-1,3-dioxin-4-one 

Downstream Products

• 310883-88-6 (2R,4R,6R)-2-[4-((E)-2-[(2R,3S,4S,5S,6R)-3,5-dimethyl-6-[2-(trimethylsilyloxyethyl)]-4-(triphenylsilyloxy)-tetrahydro-2H-pyran-2-yl]prop-1-enyl)(1,3-oxazol-2-yl)]-methyl-4-methoxy-2-(triethylsilyloxy)-6-(triethylsilyloxymethyl)-tetrahydro-2H-pyran-2-ol 
• 296785-20-1 (2S,4R,6R)-2-[4-((E)-2-[(2R,3S,4S,5S,6R)-3,5-dimethyl-6-(2-trimethylsilyloxyethyl)-4-triphenylsilyloxy-tetrahydro-2H-pyran-2-yl]prop-1-enyl)(1,3-oxazol-2-yl)]methyl-4-methoxy-6-triethylsilyloxymethyl-tetrahydro-2H-pyran-2-ol 

Relevant academic research and scientific papers

Phorboxazole B synthetic studies: Construction of C(1-32) and C(33-46) subtargets

The convergent syntheses of the C(1-32) and C(33-46) domains of phorboxazole B are described. An iterative cyclocondensation strategy exploited the Jacobsen hetero-Diels-Alder (HDA) reaction as a platform for the synthesis of both the C(5-9) and C(11-15) tetrahydropyran rings. The use of 2-silyloxydiene coupling partners bearing an increasing resemblance to the phorboxazole skeleton was found to lead to a reduction in diastereoselectivity, however, in the case of the C(11-15) ring. The coupling of aldehyde 21 and 2-silyloxydiene 20 by this route provided a C(1-32) fragment which was elaborated to the macrolide core of phorboxazole B. The synthesis of the C(33-46) domain involved a Nozaki-Kishi coupling of aldehyde 31 and vinyl iodide 39. The syntheses of 31 and 39 were highly diastereoselective: an Evans [Cu(Ph-pybox)](SbF6)2-catalysed Mukaiyama aldol reaction formed the cornerstone of the synthesis of 31 whilst a Nagao-Fujita acetate aldol reaction provided a convenient means of installing the sole stereogenic centre of 39.

Application of complex aldol reactions to the total synthesis of phorboxazole B

The synthesis of phorboxazole B has been accomplished in 27 linear steps and an overall yield of 12.6%. The absolute stereochemistry of the C4-C12, C33-C38, and C13-C19 fragments was established utilizing catalytic asymmetric aldol methodology, while the absolute stereochemistry of the C20-C32 fragment was derived from an auxiliary-based asymmetric aldol reaction. All remaining chirality was incorporated through internal asymmetric induction, with the exception of the C43 stereocenter which was derived from (R)-trityl glycidol. Key fragment couplings include a stereoselective double stereodifferentiating aldol reaction, a metalated oxazole alkylation, an oxazole-stabilized Wittig olefination, and a chelation-controlled addition of the fully elaborated alkenyl metal side chain.

Asymmetric synthesis of phorboxazole B - Part I: Synthesis of the C20-C38 and C39-C46 subunits

The total synthesis of the antitumor marine macrolide phorboxazole B (1) has been realized. The phorboxazoles are representative of a new structural class of macrolides and are among the most cytostatic natural products known: inhibiting the growth of tum