Tiglic aldehyde, diethyl acetal

Tiffeneau rearrangement, 34, 19 Tiglic aldehyde, diethyl acetal, 32, 5 Tin, tetraethyl-, 36, 86 Tin tetrachloride, 36, 87 o-Tolualdehyde, 30, 99 TOLUENE-a,a-DIOL, 0-NITRO-, DIACETATE, 36, 58... 

This afforded primary alcohol 18, which was oxidized to the aldehyde and the latter subjected to Z-selective StiU-Gennari olefination to a,P-enoate 19. Treatment of 19 under acidic conditions caused complete desilylation and lactonization, giving dihydropyrone 20. Debenzylation and protection of the vicinal diol moiety gave acetonide 21, which was converted into (+)-phomopsolide B by means of esterification with tiglic add followed by acetal deavage [8g]. In this synthesis, the two stereocenters of the starting diethyl n-tartrate become carbon atoms C-5/C-6 of the final dihydropyrone ring. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

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