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Organic Synteses vol 69 - Paquette L.A.

Paquette L.A., Boecman R.K. Organic Synteses vol 69 - John Wiley & Sons, 1990. - 174 p.
ISBN 0-471-54560-0
Download (direct link): organicsynthesesvol691990.pdf
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SUBMISSION OF PREPARATIONS
Organic Syntheses welcomes and encourages submission of experimental procedures which lead to compounds of wide interest or which illustrate important new developments in methodology. The Editorial Board will consider proposals in outline format as shown below, and will request full experimental details for those proposals which are of sufficient interest. Submissions which are longer than three steps from commercial sources or from existing Organic Syntheses procedures will be accepted only in unusual circumstances.
Organic Syntheses Proposal Format
1) Authors
2) Title
3) Literature reference or enclose preprint if available.
4) Proposed sequence
5) Best current alternative(s)
6) a. Proposed scale, final product:
b. Overall yield:
c. Method of isolation and purification:
d. Purity of product (%):
e. How determined?
7) Any unusual apparatus or experimental technique:
8) Any hazards?
9) Source of starting material?
10) Utility of method or usefulness of product.
Submit to: Dr. Jeremiah P. Freeman, Secretary Department of Chemistry University of Notre Dame Notre Dame, IN 46556
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Proposals will be evaluated in outline form, again after submission of full experimental details and discussion, and, finally by checking experimental procedures. A form that details the preparation of a complete procedure (Notice to Submitters) may be obtained from the Secretary.
Additions, corrections, and improvements to the preparations previously published are welcomed; these should be directed to the Secretary. However, checking of such improvements will only be undertaken when new methodology is involved. Substantially improved procedures have been included in the Collective Volumes in place of a previously published procedure.
ACKNOWLEDGMENT
Organic Syntheses wishes to acknowledge the contributions of Hoffmann-LE Roche, Inc., Merck & Co. and the Rohm and Haas Co. to the success of this enterprise through their support, in the form of time and expenses, of members of the Boards o Directors and Editors.
viii
PREFACE
Like its predecessors, this volume contains checked and edited procedures dealing with important new synthetic methods or specific compounds holding potential interest for synthetic chemists. The compilation begins with three procedures detailing kinetic resolution by enzymatic means. Of these, the preparations of (-)-(1R,2S)-and (+)-(1 S,2R)-trans-2-PHENYLCYCLOHEXANOL and ETHYL (R)- and (S)-2-FLUOROHEXANOATE rely on lipase-catalyzed ester hydrolysis. The use of pig liver esterase for enantioselective saponification is nicely demonstrated in the case of (1S,2S,3R)-3-HYDROXY-2-NITROCYCLOHEXYL ACETATE. The next group of entries constitute a cluster of five stereocontrolled processes that have proven useful for constructing relative complex molecules. In the first, which targets (4RS,4aRS,6RS,8aRS)-, (4S,4aS,6S,8aS)-, and (4R,4aR,6R,8aR)-4-METHOXYCARBONYL-1,1,6-TRIM ETHYL-1,4,4a,5,6,7,8,8a-OCTAH YDRO-
2,3-BENZOPYRONE, an intramolecular Diels-Alder reaction is responsible for the diastereoselectivity. The stereoselective 1,4-functionalization of 1,3-dienes is exemplified by a two-step process leading to cis- and trans-1-ACETOXY-4-(DICARBOMETHOXYMETHYL)-2-CYCLOHEXENE. The effectiveness of a silyl hydride in providing a means for erythro-directed reduction of a p-keto amide is applied in a route to ERYTHRO-1-(3-H YD ROXY-2-M ETHYL-3-PH ENYL-PROPANOYL)PIPERIDINE. This is followed by an asymmetric synthesis based on a chiral bicyclic lactam leading to (R)-4-ETHYL-4-ALLYL-2-CYCLOHEXEN-1-ONE. The stereoselectivity with which acetoxy migration can operate to an adjacent radical center is reflected in the one-step reaction that gives rise to 1,3,4,6-TETRA-
O-ACETYL-2-DEOXY-a-D-GLUCOPYRANOSE.
The third set of procedures focuses on the vital role that organometallic reagents play in the transformation of functional groups. The first of the seven
illustrative examples provides details on the use of the Tebbe reagent for effecting the methylenation of esters. The two model systems are 1-PHENOXY-1-PHENYLETHENE and 3.4-DIHYDRO-2-METHYLENE-2H-1 -B ENZOPYRAN. In a similar vein, the efficacy with which mixed higher-order cyanocuprates can realize the opening of epoxides is demonstrated in the preparation of 1-BENZYLOXY-4-PENTEN-2-OL. Silicon-containing Grignard reagents are rapidly being developed as versatile and utilitarian reagents. In this context, the procedure to make TRIMETHYL(2-METHYLENE-4-PHENYL-3-BUTENYL)SILANE is a specific example of a one-step conversion of esters to allylsilanes. The readiness with which the nucleophilic hydroxyméthylation of carbonyl compounds can be realized is illustrated by the formation of 1-(HYDROXYMETHYL)CYCLOHEXANOL. A different use of Grignard chemistry is reflected in the hydromagnesiation of propargylic alcohols to afford (E)-3-PENTYL-2-NONENE-1,4-DIOL. New uses of lithium organometallics are illustrated in conjunction with in situ generation of acyllithium reagents from carbon monoxide as used in making 3-HYDROXY-2,2,3-TRIMETHYLOCTAN-4-ONE, and with the propargylation of alkyl halides as employed for gaining access to (E)-6,10-DIMETHYL-5,9-UNDECADIEN-1-YNE and (E)-7,11-DIMETHYL-6, IO-DOD EC ADIEN-2-YN-1-OL.
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