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5-Alpine borane

Fig. 7. Preparation of Alpine-borane (93) and use in the synthesis of homochiral butyrolactones and arylhydroxytetronic acids. Rg and denote small and... Fig. 7. Preparation of Alpine-borane (93) and use in the synthesis of homochiral butyrolactones and arylhydroxytetronic acids. Rg and denote small and...
Enantioselective reduction is not possible for aldehydes, since the products are primary alcohols in which the reduced carbon is not chiral, but deuterated aldehydes RCDO give a chiral product, and these have been reduced enantioselectively with B-(3-pinanyl)-9-borabicyclo[3.3.1]nonane (Alpine-Borane) with almost complete optical purity. ... [Pg.1201]

S-Alpine-borane and i -Alpine-borane are derived from either (-)-a-pinene or (+)-a-pinene and 9-borabicyclo[3.3.1]nonane (9-BBN). [Pg.468]

The synthesis of chiral liquid-crystalline allenes was reported by Tschierske and co-workers (Scheme 4.10) [14]. An asymmetric reduction of 41 with Alpine borane was a key step to an enantioenriched allene 44. After removal of the silyl group, the allenic alcohol was etherified by the Mitsunobu method to give 45, the first liquid-crystalline allene derivatives. [Pg.146]

Highly enantioenriched 4-alken-l-yn-3-ol moieties present in many bioactive acetylenic metabolites from sponges have been efficiently obtained by reduction of the parent 1-trimethylsilyI-4-alken-l-yn-3-one 18 with Alpine-borane or with BH3-SMe2 in the presence of chiral oxazaborolidines, followed by desilylation of the resulting alcohol. This strategy has been applied to the first stereoselective synthesis of petrofuran 19 <99SL429>. [Pg.146]

The field of organoboron chemistry pioneered by Brown [40] also provides a wealth of excellent transformations. Consider the asymmetric reduction of carbonyl compounds by Alpine-Borane [41]. Alpine-Borane is prepared by the following sequence ... [Pg.11]

In the second step, achiral 9-borabicyclo[3.3.1]nonane (9-BBN) adds to the less hindered diastereotopic face of a-pinene to yield the chiral reducing agent Alpine-Borane. Aldehydes are rapidly reduced to alcohols. The reaction with deuterio-Alpine-Borane, which yields (R)-a-d-henzy alcohol in 98% enantiomeric excess ( ) reveals a very high degree of selectivity of the enantiotopic faces of the aldehyde group in a crowded transition state ... [Pg.12]

B-3-Pinanyl-9-borabicyclo 3.3.1 nonane, 8,403 9, 320 321 10,320 321. The reagent is available from Aldrich as Alpine Borane . [Pg.557]


See other pages where 5-Alpine borane is mentioned: [Pg.46]    [Pg.47]    [Pg.31]    [Pg.247]    [Pg.569]    [Pg.1201]    [Pg.1208]    [Pg.362]    [Pg.372]    [Pg.145]    [Pg.146]    [Pg.147]    [Pg.386]    [Pg.386]    [Pg.386]    [Pg.668]    [Pg.11]    [Pg.12]    [Pg.12]    [Pg.12]    [Pg.915]    [Pg.31]    [Pg.12]    [Pg.12]    [Pg.360]    [Pg.1102]    [Pg.46]    [Pg.46]    [Pg.46]    [Pg.47]   
See also in sourсe #XX -- [ Pg.145 ]

See also in sourсe #XX -- [ Pg.91 , Pg.212 ]

See also in sourсe #XX -- [ Pg.91 , Pg.212 ]

See also in sourсe #XX -- [ Pg.140 ]

See also in sourсe #XX -- [ Pg.176 ]




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Aldehydes with alpine-borane

Aldehydes with deuterated alpine-borane

Alpine borane reaction with aldehydes

Alpine borane, enantioselective

Alpine borane, enantioselective reductions

Alpine boranes

Alpine boranes

Alpine-Borane methyl ketone

Boranes Alpine-Borane

Enantioselectivity, with Alpine borane

Esters Alpine borane

Ketone with neat Alpine-Borane

Ketones Alpine borane

Ketones asymmetric reduction with Alpine-borane

Ketones with Alpine-Borane

Ketones, a,P-alkynyl Alpine borane

Ketones, a-halo Alpine borane

Ketones, reaction with Alpine borane

Midland Alpine-Borane

Midland Alpine-Borane reduction

Nitriles, a-ketoreduction Alpine borane

Preparation alpine borane

R-Alpine borane

Reduction Alpine borane

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