220156-18-3

Upstream product

• 130874-89-4 (2R,3R)-1,4-dimethoxy-1,1,4,4-tetraphenyl-2,3-butandiol 
• 13292-87-0 dimethyl sulfide borane 
• 199185-13-2 (4R,5R)-4,5-Bis-(methoxy-diphenyl-methyl)-2-((1S,2S)-2-pentyl-cyclopropyl)-[1,3,2]dioxaborolane 
• 199185-03-0 (4R,5R)-2-((E)-Hept-1-enyl)-4,5-bis-(methoxy-diphenyl-methyl)-[1,3,2]dioxaborolane 
• 130888-43-6 (4R,5R)-4,5-bis(methoxymethyl)-2-(p-methoxyphenyl)-α,α,α',α'-tetraphenyl-1,3-dioxolane 

Downstream Products

• 220156-24-1 (4R,5R)-2-[(E)-2-[3-tert-butyl(dimethyl)siloxymethyl]ethenyl]-4,5-bis[methoxy(diphenyl)methyl]-1,3,2-dioxaborolane 
• 199185-09-6 (4R,5R)-4,5-Bis-(methoxy-diphenyl-methyl)-2-((E)-styryl)-[1,3,2]dioxaborolane 
• 199185-05-2 (4R,5R)-2-((E)-Hex-1-enyl)-4,5-bis-(methoxy-diphenyl-methyl)-[1,3,2]dioxaborolane 
• 220156-28-5 (4R,5R)-2-hydroxy-4,5-bis[methoxy(diphenyl)methyl]-1,3,2-dioxaborolane 
• 251956-33-9 (4R,5R)-2-[(E)-2-{hydroxymethyl}ethenyl]-4,5-bis[methoxy(diphenyl)methyl]-1,3,2-dioxaborolane 
• 321882-74-0 (4'R,5'R)-2-[4',5'-bis(methoxydiphenylmethyl)-1',3',2'-dioxaborolan-2'-yl]prop-2-en-1-ol 
• 199185-13-2 (4R,5R)-4,5-Bis-(methoxy-diphenyl-methyl)-2-((1S,2S)-2-pentyl-cyclopropyl)-[1,3,2]dioxaborolane 
• 199185-21-2 (1'R,2'R,4R,5R)-4,5-bis(methoxydiphenylmethyl)-2-(2'-phenylcyclopropyl)-1,3,2-dioxaborolane 
• 321882-78-4 (4R,5R,1'R,2'R)-2-[2-(hydroxymethyl)cyclopropyl]-4,5-bis[methoxy(diphenyl)methyl]-1,3,2-dioxaborolane 
• 130874-89-4 (2R,3R)-1,4-dimethoxy-1,1,4,4-tetraphenyl-2,3-butandiol 

Relevant academic research and scientific papers

[3,3] Sigmatropic Rearrangement of Boron-Containing Allyl Alcohols: Synthesis of Allyl Addition Reagents

Enantiomerically pure reagents for allyl additions were prepared by [3,3] sigmatropic rearrangements (see scheme) followed by a separation of the diastereoisomers. The highly stable allylboronic esters with a stereogenic center α to a boron atom were used to synthesize Z-configured homoallylic alcohols with an enantiomeric excess > 94%.

Enantiomerically pure cyclopropylboronic esters: Auxiliary- versus substrate-control

Stable, enantiomerically pure cyclopropylboronic esters are synthesized from alkynes by a hydroboration-cyclopropanation sequence. The direct hydroboration - utilizing 1,3,2-dioxaborolane 4 - is most convenient, however, with more functionalized side-chains it failed to give the desired intermediates. Using the more reactive dicyclohexylborane, followed by oxidation and transesterification, is a good alternative one-pot conversion. Cyclopropanations were performed either following a Simmons-Smith protocol or with diazomethane-palladium(II) acetate. The influence on the diastereoselectivity of the auxiliary 1 is compared with the influence of an additional stereogenic center in the side-chain. The Royal Society of Chemistry 2000.

Synthesis of enantiomerically pure cyclopropanes from cyclopropylboronic acids

A general method for the stereocontrolled synthesis of cyclopropanes is described. Various, highly stable, enantiomerically pure alkenylboronic esters 13 have been conveniently synthesized by the direct hydroboration of alkynes 11 using the new chiral 1,3,2-dioxaborolane 15. The high stability was also demonstrated by the selective deprotection of a tert- butyldimethylsilyl protecting group without hydrolyzing the boronic ester. The diastereoselective cyclopropanation of the olefins was achieved by the palladium(II) acetate catalyzed decomposition of diazomethane. This process was optimized giving cyclopropylboronic esters 20/21 in high yield (89-99%) and with good to excellent diastereomeric ratios (up to 95:5). The diastereomers were separated by means of MPLC and their configurations determined by X-ray crystallography (compound 21c), by transformation to known cyclopropanols, and by correlation of NMR data. Treatment with LiAlH4 followed by acidic hydrolysis yielded the enantiomerically pure cyclopropylboronic acid 27 for the first time and allowed the nearly quantitative recovery of the chiral auxiliary 3. Different protocols for the Suzuki coupling reaction of compound 27 were investigated.