Total synthesis of (+)-monocerin via tandem dihydroxylation-S_N2 cyclization and a copper mediated tandem cyanation–lactonization approach

Abstract

A simple and novel synthesis of (+)-monocerin was achieved in 15 steps and 15.5% overall yield from 3-buten-1-ol employing hydrolytic kinetic resolution, Julia olefination, intramolecular tandem Sharpless asymmetric dihydroxylation-SN2 cyclization and a novel copper mediated tandem cyanation-cyclization as the key steps.

AlternariaMycotoxins in Food and Feed: An Overview

“…Monocerin and its analogues were proven to be nonspecific toxins and nonspecific seed germination inhibitors by their interference with selected stages of cell division cycles. In recent years, they have attracted greater interest; consequently, several syntheses of this molecule have been reported [45].…”

An alternative stereoselective total synthesis of Verbalactone

“…While compound 2 could be obtained from opening of epoxide 4 with 2-pentyl-1,3-dithiane 3, the 1,3-dithiane 3 could be prepared from the aldehyde 5. The synthesis (Scheme 2) was started from the commercially available hexanal 5, which was converted as corresponding 1,3-dithiane using 1,3-propanedithiol and BF 3• OEt 2 in CH 2 Cl 2 for 12 h. Later, 1,3-dithiane 3 on treatment with n-BuLi followed by the regioselective opening of known epoxide 4 28 with resulting carbanion gave alcohol 6 in 77% yield. Later, the 1,3-dithioacetal group was removed from 6 to furnish the β-hydroxy ketone 7.…”

Short Stereoselective Synthesis of (+)-Monocerin via a Palladium-Catalysed Intramolecular Alkoxycarbonylation

“…The crude product was purified by column chromatography on silica gel using hexane/ethyl acetate as an eluent to afford the pure product. Clear oil (231 mg, 72%); [α] 25 D +13.1 (c 1.0, CHCl 3 ) [lit 12 (+)-Monocerin (1): To the compound 11 (0.1 g, 0.3 mmol) in dichloromethane, boron tribromide (1.0 M in hexanes, 0.1 mL, 1 mmol) was added at -25 °C. The reaction mixture was warmed to room temperature and stirred for 2 h. The reaction was quenched by the addition of saturated aqueous NaHCO 3 solution and the product was extracted with dichloromethane (3 × 20 mL).…”

“…Colourless oil (0.058 g) 55%; [α] 25 D +54.1 (c 1.0, CHCl 3 ) [lit. 12 SA thank the Sadhvi Pharma for providing the financial assistance to carry out part of this work.…”

“…8 Fujita et al synthesised monocerin via a stereoselective oxylactonisation of orthoalkenylbenzoate with chiral hypervalent iodine. 9 Through intramolecular trapping of quinonemethide by She et al 10,11 and copper mediated tandem cyanation-lactonisation by Nookaraju et al 12 we synthesised a monocerin. Herein, we report a short stereoselective total synthesis of monocerin 1 by a palladium catalysed intramolecular carbonylation using carbon monoxide.…”