Chemo-enzymatic preparation of optically active endo-bicyclo[4.1.0]heptan-2-ols

Barnier, J. P.; Morisson, Vèronique; Volle, Isabelle; Blanco, Luis

doi:10.1016/s0957-4166(99)00099-3

Cited by 18 publications

(14 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, readily available bromoaldehyde 5 4 was debenzylated (AlCl 3 , 80 % yield)5 and selectively oxidized with PhI(CF 3 CO 2 ) 2 6 to the expected p ‐quinone (97 % yield), which was reduced with Na 2 S 2 O 4 to the corresponding dihydroquinone and protected with SEM groups (SEMCl, i Pr 2 NEt, 92 % yield for two steps) to afford bromoaldehyde 6 . Meanwhile, enantioselective asymmetric dihydroxylation of enone 8 7 (AD‐mix‐β, single recrystallization, 69 % yield, >95 % ee )8 afforded the corresponding 1,2‐diol, whose protection (2‐methoxypropene, PPTS) furnished acetonide 9 in 94 % yield. Conversion of the latter into its TMS enol ether (TMSOTf, Et 3 N), and subsequent exposure to O 2 in the presence of catalytic amounts of Pd(OAc) 2 ,9 led to enone 10 (83 % yield), whose iodination (I 2 , py) afforded iodoenone 7 in 91 % yield.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of the Monomeric Unit of the Lomaiviticin Aglycon

Nicolaou

Nold

2009

Angew Chem Int Ed

View full text Add to dashboard Cite

[3] In this communication, we describe the total synthesis of the monomeric aglycon unit (3, Figure 1) of the lomaiviticins, which is reminiscent of the kinamycins (i.e. kinamycin C, 4, Figure 1).The dimeric structure of the lomaiviticins renders itself to a symmetrical retrosynthetic dissection through the center of the molecule, revealing monomeric unit 3 (see Figure 2) as a possible precursor to both 1 and 2, a scenario that might not be so dissimilar to their biosynthetic pathway. Our approach to enantiopure pre-lomaiviticin structure 3 followed our general strategy towards the kinamycins[4] (defining bromo-aldehyde 5 and iodo-enone 7 as the possible building blocks as shown in Figure 2), and involved an Ullmann coupling reaction and a benzoin-type cyclization as the main processes to construct its molecular framework. However, it required special design features (e.g. substrate 6, vide infra, in order to achieve high regiocontrol) and the development of a novel samarium-mediated allylic hydroxyl group transposition (vide infra) that allowed significant shortening of the synthetic route.The required building blocks 6 and 7 were synthesized from starting materials 5 and 8, respectively, as summarized in Scheme 1. Thus, readily available bromo-aldehyde 5[4] was debenzylated (AlCl 3 , 80 % yield) [5] and selectively oxidized with PhI(CF 3 CO 2 ) 2 [6] to the expected p-quinone (97 % yield), which was reduced with Na 2 S 2 O 4 to the corresponding dihydroquinone and protected with SEM groups (SEMCl, iPr 2 NEt, 92 % yield for two steps) to afford bromo-aldehyde 6. On the other hand, and as shown in Scheme 1, enantioselective asymmetric dihydroxylation of enone 8[7] (AD-mix β, single recrystallization, 69 % yield, >95 % ee) [8] afforded the corresponding 1,2-diol, whose protection (2-methoxypropene, PPTS) furnished acetonide 9 in 94 % yield. Conversion of the latter to its TMS-enol ether (TMSOTf,

show abstract

Section: Methodsmentioning

confidence: 99%

Synthesis of the Monomeric Unit of the Lomaiviticin Aglycon

Nicolaou

Nold

2009

Angew Chem Int Ed

View full text Add to dashboard Cite

show abstract

“…The known enone [14] 21 was subjected to Coreys asymmetric reduction by utilizing the chiral oxazaborolidine. [15] However, the enantiomeric excess of the chiral allyl alcohol (+)-22 proved to be 77 % ee by chiral HPLC analysis.…”

Section: Resultsmentioning

confidence: 99%

“…2-Iodo-3-undecylcyclohex-2-enone (23): Azidotrimethylsilane (1.3 mL, 5.0 mmol) was added to a stirred solution of the known enone [14] 21 (91.6 mg, 0.36 mmol) in CH 2 Cl 2 (0.5 mL) at 0 8C under N 2 . After the reaction mixture had been stirred for 2 h, I 2 (1.28 g, 5.0 mmol) in CH 2 Cl 2 www.chemeurj.org (0.54 mL) and pyridine (3.0 mL) were added dropwise.…”

mentioning

confidence: 99%

Facile and Efficient Synthesis of Lactols by a Domino Reaction of 2,3‐Epoxy Alcohols with a Hypervalent Iodine(III) Reagent and Its Application to the Synthesis of Lactones and the Asymmetric Synthesis of (+)‐Tanikolide

Fujioka

Matsuda

Horai

et al. 2007

Chemistry A European J

View full text Add to dashboard Cite

The domino reaction of 2,3-epoxy-1-alcohol derivatives, namely tetrasubstituted 2,3-epoxy-1-alcohols and 2- or 3-alkyl trisubstituted 2,3-epoxy-1-alcohols, with PhI(OCOCF(3))(2) in the presence of H(2)O is described in detail. In this reaction, several types of lactol derivatives can be directly obtained from the 2,3-epoxy-1-alcohol derivatives in a single operation. The obtained lactols were successively converted into the corresponding lactones. This reaction is applicable to the construction of optically active lactone compounds. The asymmetric total synthesis of (+)-tanikolide, an antifungal marine natural product, has been effectively achieved by using this reaction.

show abstract

“…Thus, readily available bromoaldehyde 5 [4] was debenzylated (AlCl 3 , 80 % yield) [5] and selectively oxidized with PhI(CF 3 CO 2 ) 2 [6] to the expected p-quinone (97 % yield), which was reduced with Na 2 S 2 O 4 to the corresponding dihydroquinone and protected with SEM groups (SEMCl, iPr 2 NEt, 92 % yield for two steps) to afford bromoaldehyde 6. Meanwhile, enantioselective asymmetric dihydroxylation of enone 8 [7] (AD-mix-b, single recrystallization, 69 % yield, > 95 % ee) [8] afforded the corresponding 1,2-diol, whose protection (2-methoxypropene, PPTS) furnished acetonide 9 in 94 % yield. Conversion of the latter into its TMS enol ether (TMSOTf, Et 3 N), and subsequent exposure to O 2 in the presence of catalytic amounts of Pd(OAc) 2 , [9] led to enone 10 (83 % yield), whose iodination (I 2 , py) afforded iodoenone 7 in 91 % yield.…”

mentioning

confidence: 99%

Synthesis of the Monomeric Unit of the Lomaiviticin Aglycon

Nicolaou

Nold

2009

Angewandte Chemie

View full text Add to dashboard Cite

Reported in 2001, lomaiviticins A (1) and B (2; Scheme 1) were isolated from Micromonospora lomaivitiensis and demonstrated striking molecular architectures and impressive antitumor and antibiotic activities against a variety of cancer cell lines and bacteria. [1] These natural products apparently exert their action through a novel mechanism involving the cleavage of DNA. [2] Their chemical synthesis presents a formidable challenge, and reports describing partial success have already appeared. [3] Herein, we describe the synthesis of the monomeric aglycon unit of the lomaiviticins (3; Scheme 1), which is reminiscent of the kinamycins (i.e. kinamycin C (4); Scheme 1).The dimeric structure of the lomaiviticins renders itself to a symmetrical retrosynthetic dissection through the center of the molecule. This dissection reveals monomeric unit 3 (Scheme 2) as a possible precursor to both 1 and 2-a scenario that might not be so dissimilar to their biosynthetic pathway. Our approach to enantiopure pre-lomaiviticin structure 3 followed our general strategy towards the kinamycins [4] (defining bromoaldehyde 5 and iodoenone 7 as the possible building blocks as shown in Scheme 2), and involved an Ullmann coupling reaction and a benzoin-type cyclization as the main processes to construct its molecular framework. However, the approach required special design features (e.g. substrate 6, see below, to achieve high regiocontrol) and the development of a novel samarium-mediated 1,3-allylic hydroxy group transposition (see below) that allowed significant shortening of the synthetic route.The required building blocks 6 and 7 were synthesized from starting materials 5 and 8, respectively, as summarized in Scheme 3. Thus, readily available bromoaldehyde 5 [4] was debenzylated (AlCl 3 , 80 % yield) [5] and selectively oxidized with PhI(CF 3 CO 2 ) 2[6] to the expected p-quinone (97 % yield), which was reduced with Na 2 S 2 O 4 to the corresponding dihydroquinone and protected with SEM groups (SEMCl, iPr 2 NEt, 92 % yield for two steps) to afford bromoaldehyde 6. Meanwhile, enantioselective asymmetric dihydroxylation of enone 8 [7] (AD-mix-b, single recrystallization, 69 % yield, > 95 % ee) [8] afforded the corresponding 1,2-diol, whose protection (2-methoxypropene, PPTS) furnished acetonide 9 in 94 % yield. Conversion of the latter into its TMS enol ether (TMSOTf, Et 3 N), and subsequent exposure to O 2 in the presence of catalytic amounts of Pd(OAc) 2 , [9] led to enone 10 (83 % yield), whose iodination (I 2 , py) afforded iodoenone 7 in 91 % yield.Scheme 1. Structures of lomaiviticins A (1) and B (2), their monomeric unit (3), and kinamycin C (4).Scheme 2. Retrosynthetic analysis of lomaiviticin aglycon monomer 3. Bn = benzyl, SEM = 2-(trimethylsilyl)ethoxymethyl.

show abstract

Chemo-enzymatic preparation of optically active endo-bicyclo[4.1.0]heptan-2-ols

Cited by 18 publications

References 31 publications

Synthesis of the Monomeric Unit of the Lomaiviticin Aglycon

Synthesis of the Monomeric Unit of the Lomaiviticin Aglycon

Facile and Efficient Synthesis of Lactols by a Domino Reaction of 2,3‐Epoxy Alcohols with a Hypervalent Iodine(III) Reagent and Its Application to the Synthesis of Lactones and the Asymmetric Synthesis of (+)‐Tanikolide

Synthesis of the Monomeric Unit of the Lomaiviticin Aglycon

Contact Info

Product

Resources

About