Stereoselective synthesis of 1,6-dioxaspiro[4.5]decane chiral spiroketal skeleton via C2-symmetric approach using crossmetathesis

A common asymmetric approach for the synthesis of a 1,6-dioxaspiro[4.5]decane chiral spiroketal system, which is a subunit of various natural products, is described and the key aspects of the synthesis are self-crossmetathesis and exploitation of C2-symmetric of the metathesis product 5 to obtain the required chiral spiroketal.

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(S)-((2-(Methoxymethoxy)hex-5-enyloxy)methyl)benzeneC15H22O3[α]D32=-42 (c 1, CH2Cl2)Source of chirality: asymmetric synthesisAbsolute configuration: (2S)

(5R,12S,E)-5,12-Bis(benzyloxymethyl)-2,4,13,15-tetraoxahexadec-8-eneC28H40O6[α]D32=-9.2 (c 1.25, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,12S,E)

(5R,12S)-5,12-Bis(benzyloxymethyl)-2,4,13,15-tetraoxahexadecan-8-olC28H42O7[α]D32=-7.6 (c 1.2, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,12S)

(5R,12S)-5,12-Bis(benzyloxymethyl)-2,4,13,15-tetraoxahexadecan-8-oneC28H40O7[α]D32=-21.4 (c 1.3, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,12S)

(2S,5R,7S)-2,7-Bis(benzyloxymethyl)-1,6-dioxaspiro[4.5]decaneC24H30O7[α]D32=+18.2 (c 1.1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (2S,5R,7S)

(2S,5R,7S)-1,6-Dioxaspiro[4.5]decane-2,7-diyldimethanolC10H18O4[α]D32=+69.9 (c 1.25, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (2S,5R,7S)