Π-facial Selectivity Research Articles

New camphor-derived auxiliaries in methoxyselenylation and methoxybromination with opposite diastereofacial selectivity : Preparation of β-amino alcohol chiral synthons

Methoxyselenylation and methoxybromination of chiral 3-acyl-2-oxazolones with PhSeCl/MeOH and Br 2/MeC(OMe) 3 smoothly proceed to result in highly stereoselective formation of chiral synthons for β-amino alcohols, but with opposite π-facial selectivity.

Allylic stereocentre directed cyclopropanation. A new highly enantioselective synthesis of hemicaronic aldehyde

isopropylidenetriphenylphosphorane reacts with oxazolidine 4 with excellent π-face selectivity. The title compound is obtained in high optical purity after removal of the chiral auxiliary.

Aldol reactions in polypropionate synthesis: High π-face selectivity of enol borinates from α-chiral methyl and ethyl ketones under substrate control

Use of ( c-C 6H 11) 2BCl in the anti-selective aldol reaction of the α-chiral ethylketone 2 leads to high stereoselectivity (>94%) for the 1,2- anti-2,4- anti isomer 7. The related α-chiral methylketone aldol reaction, 8 → 9, proceeds with 84–93% diasteroselectivity for a range of boron reagents.

A [(4 + 2)+(3 + 2)] approach to a forskolin intermediate; a further understanding of π-facial selection in Diels–Alder reactions

The preparation of a highly oxygenated decalin derivative suitable for use in the construction of the adenylate cyclase activator forskolin is described; the facial selectivity has been clarified by a crystal structure determination.

ChemInform Abstract: A NEW DIENE PERMITTING EVALUATION OF FACIAL SELECTIVITY IN DIELS‐ALDER ADDITIONS AND PREPARATION OF A NORBORNADIENONE

AbstractDas über das Dibromid (III) zugängliche Dimethylen‐norbornenon (IV) reagiert mit Dienophilen (VI) und (VIII) zu den Verbindungen (VII) bzw. (X).

A model study for the synthesis of the hexahydrobenzofuran fragment of the milbemycins and avermectins.

An INOC based approach to the hexahydrobenzofuran portion of the milbemycins and the avermectins is described in which a high level of π-facial selectivity has been observed in a six-membered ring forming reaction.

A new diene permitting evaluation of facial selectivity in Diels–Alder additions and preparation of a norbornadienone

The reaction of 5,6-dimethylene-1,4-dimethyl-2,3-diphenylnorborn-2-en-7-one (6) with dienophile, is used as a probe for π-facial selectivity in Diels–Alder reactions and is shown to proceed through norbornadien-7-ones, one of which exhibits moderate stability.

Asymmetric diels-alder reaction of a chiral allenic ester : enantioselective synthesis of (−)-β-santalene

The Lewis-acid promoted Diels-Alder reaction of the allenic ester 10 provides the adduct 11 with excellent π-facial selection leading to an efficient enantioselective synthesis of (−)-β-santalene and to the recovery of the chiral control element 7 .