Stereoselective Synthesis of syn,syn- and syn,anti-1,3,5-Triols via Intramolecular Hydrosilylation of Substituted Pent-3-en-1,5-diols

Abstract

A stereoselective method for synthesis of syn,syn- and syn,anti-1,3,5-triols based on a double allylboration-intramolecular hydrosilylation sequence has been developed. 1,3-Syn stereocontrol is achieved in the intramolecular hydrosilylation of mono-protected (Z)-1,5-syn-diols and (E)-1,5-anti-diols with 87:13 to 95:5 and 86:14 to 88:12 diastereomeric ratios, respectively, by using 0.5 mol % of Karstedt’s catalyst in toluene.

Synthesis of Polyketide Stereoarrays Enabled by a Traceless Oxonia‐Cope Rearrangement

“…The corresponding 1,5‐pentendiols can be readily converted into versatile polyol building blocks. It is known from the work of the group of Roush14 that the syn selectivity of hydrosilylation was proposed to go through a chairlike transition state with a pseudoequatorial olefin group. Interestingly, the opposite trans selectivity ( ds 20:1) was obtained with the 1,5‐pentenediol 3 q (Scheme ).…”

Synthesis of Polyketide Stereoarrays Enabled by a Traceless Oxonia‐Cope Rearrangement

“…The corresponding 1,5-pentendiols can be readily converted into versatile polyol building blocks. It is known from the work of the group of Roush [14] that the syn selectivity of hydrosilylation was proposed to go through a chairlike Table 3: Preparation of (E)-2-alkyl-1,5-pentenediols through an oxonia-Cope rearrangement. [a,b] [a] Reaction conditions: rac-2 (0.15-0.25 mmol), SiCl 4 (0.5-1. .…”

Gram Scale Synthesis of the C(18)−C(34) Fragment of Amphidinolide C

“…12 Unfortunately, initial attempts at reproducing the allylation conditions using 27 or 30 were unsuccessful, resulting in complex reaction mixtures. Met with early complications, this route was quickly abandoned, mostly due to the product not containing the desired vinylstannane moiety required for Stille cross-coupling.…”