Stereoselective total synthesis and structural revision of the diacetylenic diol natural products strongylodiols H and I.

Pamarthi Gangadhar,Sayini Ramakrishna,Ponneri Venkateswarlu,Pabbaraja Srihari

doi:10.3762/bjoc.14.206

Pamarthi Gangadhar, Sayini Ramakrishna + Show 2 more

Open Access

https://doi.org/10.3762/bjoc.14.206

Copy DOI

Abstract

The stereoselective total synthesis of strongylodiol H and I has been accomplished. The synthetic procedure comprised the stereoselective reduction of a ketone functionality in an ene–yne–one employing CBS as a catalyst and a Cadiot–Chodkiewicz coupling reaction as the key reaction steps. A common aldehyde intermediate has been used for the synthesis of both strongylodiols.

Highlights

Diacetylenic polyol compounds [1,2] originated from marine sources continue to attract significant interest owing to their structural architectures and impressive biological properties that include antibacterial [3], anticancer [4,5,6], antiviral [7] and neuritogenic activities [8]
We envisaged that the target molecules strongylodiol H (9) and strongylodiol I (10) can be synthesized by a Wittig reaction of a common intermediate aldehyde with triphenylphosphonium Wittig salts and 16, respectively, followed by the desilylation (TBDPS removal) to yield the title products
The intermediate aldehyde 14 can be synthesized from ketone 17 in a four-step sequence by a stereoselective keto reduction, TBDPS protection, TBS deprotection and an oxidation reaction

Summary

Introduction

Diacetylenic polyol compounds [1,2] originated from marine sources continue to attract significant interest owing to their structural architectures and impressive biological properties that include antibacterial [3], anticancer [4,5,6], antiviral [7] and neuritogenic activities [8]. We envisaged that the target molecules strongylodiol H (9) and strongylodiol I (10) can be synthesized by a Wittig reaction of a common intermediate aldehyde with triphenylphosphonium Wittig salts and 16, respectively, followed by the desilylation (TBDPS removal) to yield the title products. The latter compound on further treatment with K2CO3 in MeOH [26] furnished the desilylated propargylic alcohol 19 (Scheme 2).

Results

Conclusion