NOVELPEppSI ™REAGE: A NENWTS GE ANNERATIOD CATALYSTSN OF AIR FOR-STA FABCLEILITATI Pd PNRECG SATALYSTSYNTHESIS VOL. 39,38, NO.NO.1 4 •• 20062005 ROM Polymerization in Facilitated Synthesis Pd–N-Heterocyclic CarbenePolyurea-Encapsulated (NHC) Catalysts for Cross-CouplingPalladium ReactionsCatalysts sigma-aldrich.com New Products from Aldrich R&D BD3–THF Solution Stabilized with NIMBA and Alkynylboronates Me-CBS Solutions in THF Alkynylboronates participate in a variety of regio- and stereoselective The asymmetric borane reduction of prochiral ketones catalyzed by (R)- carbon–carbon bond-forming reactions including enyne cross metathesis 1 2 3 or (S)-Me-CBS provides a facile method for accessing chiral secondary (CM), Alder-ene, and Dötz annulation reactions. Products obtained alcohols.1 We are pleased to introduce N-isopropyl-N-methyl-tert-butylamine from these reactions are either alkenyl or arylboronates, which are active coupling partners in (NIMBA) stabilized BD3–THF solutions for the preparation of isotopically 2 Suzuki and Heck CH3 labeled alcohols. Amine-stabilized borane–THF solutions exhibit enhanced BPin O CH3 shelf-life over those containing other stabilizers, and additionally, higher reactions. BPin = B R 3 O CH3 levels of enantiomeric excess are obtained. Deuterium-labeled alcohols CH3 may also be synthesized through (1) Kim, M.; Lee, D. O HO D the sequence of hydroboration– OBD3 Org. Lett. 2005, 7, CH3 CH3 1865. (2) (a) Hansen, R' R' Cr(CO) oxidation of olefins. Either method (R)-Me-CBS 5 R R E. C.; Lee, D. J. Am. H3CO [Ru]+ of alcohol preparation gives high Chem. Soc. 2005, 127, [Ru] levels of deuterium incorporation R Yield (%) ee (%)D atom % 3252. (b) Hansen, OH into the substrate molecule. We R' R 100 (GC) E. C.; Lee, D. J. Am. R' H 96.6 97.0 R are also pleased to now offer Chem. Soc. 2006, 128, BPin CH3 100 (GC) 94.5 96.4 BPin (R)- and (S)-Me-CBS as solutions 8142. (3) Davies, M. R BPin NO2 91 (isolated) 97.8 98.1 OCH3 in THF, in addition to our toluene W. et al. J. Org. Chem. (CM) (Alder-ene) OCH3 100 (GC) 94.2 96.1 (Dötz annulation) solutions of the same catalysts.4 2001, 66, 3525. (1) Corey, E. J.; Helal, C. J. Angew. Chem., Int. Ed. 1998, 37, 1986. (2) Sigma- Aldrich, patent pending. (3) (a) Nettles, S. M. et al. J. Org. Chem. 2002, 67, 2970. (b) Aldrich Technical Bulletin, AL-218. (4) Sold under license. US4943635 and foreign equivalents apply. End user is granted on purchase a label license to use without 3-(tert-Butyldimethylsilyloxy)-1-butyn-1-ylboronic 8 scale limitation. acid pinacol ester, 96% 674729 H3CCH3 1 g $55.20 Si Borane-d3–THF complex solution, 1.0 M in THF, 8 C H BO S O 5 g 193.50 stabilized with 0.005 M N-isopropyl-N-methyl- 16 31 3 H3C FW: 310.31 O CH3 tert-butylamine, 97.5 atom % D B CH 667714 1 mL $28.50 O 3 CH OBD H3C 3 C4H8BD3O 3 5 x 1 mL 100.00 FW: 88.96 3-Methoxy-1-propyn-1-ylboronic acid pinacol ester, 96% 8 (R)-2-Methyl-CBS-oxazaborolidine solution, 1 M in THF 8 674710 H3CO 1 g $45.00 O CH3 674656 5 mL $91.70 B C10H17BO3 CH 5 g 179.00 O 3 [112022-81-83] H 25 mL 312.00 FW: 196.05 H3C CH3 C H BNO O 18 20 N B FW: 277.17 CH3 3,3-Dimethylbutynylboronic acid diisopropyl ester, 97% 8 639192 1 g $29.80 (S)-2-Methyl-CBS-oxazaborolidine solution, 1 M in THF 8 CH3 [121021-24-7] O 5 g 85.80 674648 5 mL $91.70 B CH3 C12H23BO2 H C O [112022-81-8] H 25 mL 312.00 3 FW: 210.12 O CH C18H20BNO 3 N B FW: 277.17 CH3 Cobalt-Catalyzed Hydroazidation Organoazides have gained considerable interest recently because of their use Potassium 2-(3,5-di-tert-butyl-2-hydroxybenzyl- 8 in click chemistry and as masked amines. Erick Carreira (ETH Hönggerberg) ideneamino)-2,2-diphenylacetate, 95% and co-workers have developed a convenient method for preparing these 676551 Ph Ph 250 mg $38.25 useful intermediates by C H KNO NCO K 1 g 114.75 Markovnikov hydroazidation Ph Ph 29 32 3 2 of olefins.1 The method NCO2K FW: 481.68 OH OH utilizes a cobalt catalyst (cat.) prepared in situ from a Schiff R3 base and Co(BF ) ·6H O in Co(BF4)2 • 6H2O (cat.) R2 4 2 2 R1 R1 H R3 + TsN3 the presence of a silane to t-BuOOH, PhSiH3 or N R2 3 [(CH3)2SiH]2O give secondary and tertiary up to 90% alkyl azides in good yields. (1) Waser, J. et al. J. Am. Chem. Soc. 2005, 127, 8294. sigma-aldrich.com LEADERSHIP IN LIFE SCIENCE, HIGH TECHNOLOGY AND SERVICE ALDRICH • BOX 355 • MILWAUKEE • WISCONSIN • USA 93 “PLEASE BOTHER US.” VOL. 39, NO. 4 • 2006 Joe Porwoll, President Aldrich Chemical Co., Inc. Aldrich Chemical Co., Inc. Sigma-Aldrich Corporation 6000 N. Teutonia Ave. Professor Andrew Whiting of the University of Durham, U.K., kindly suggested that we offer Milwaukee, WI 53209, USA vinylboronic acid 2-methyl-2,4-pentanediol ester. This reagent functions as a vinyl dianion equivalent, since it can react at either end of the double bond under Suzuki–Miyaura or Heck coupling conditions. This compound also exhibits enhanced stability and lower volatility than related vinylboronate esters. 1–3 To Place Orders (1) Lightfoot, A. P.; Maw, G.; Thirsk, C.; Twiddle, S. J. R.; Whiting, A. Tetrahedron Lett. 2003, 44, 7645. Telephone 800-325-3010 (USA) (2) Lightfoot, A. P.; Twiddle, S. J. R.; Whiting, A. Org. Biomol. Chem. 2005, 3, 3167. (3) Lightfoot, A. FAX 800-325-5052 (USA) P.; Twiddle, S. J. R.; Whiting, A. Synlett 2005, 529. or 414-438-2199 CH Mail P.O. Box 2060 O 3 B Milwaukee, WI 53201, USA CH3 O Customer & Technical Services CH3 Customer Inquiries 800-325-3010 Technical Service 800-231-8327 SAFC™ 800-244-1173 673641 Vinylboronic acid 2-methyl-2,4-pentanediol ester, 95% 1 g $30.20 Custom Synthesis 800-244-1173 (4,4,6-Trimethyl-2-vinyl-1,3,2-dioxaborinane) 10 g 211.50 Flavors & Fragrances 800-227-4563 Naturally, we made this useful reagent. It was no bother at all, just a pleasure to be International 414-438-3850 able to help. 24-Hour Emergency 414-438-3850 Web Site sigma-aldrich.com Email [email protected] Do you have a compound that you wish Aldrich could list, and that would help you in your research by saving you time and money? If so, please send us your suggestion; we will be General Correspondence delighted to give it careful consideration. You can contact us in any one of the ways shown Editor: Sharbil J. Firsan, Ph.D. on this page and on the inside back cover. P.O. Box 355, Milwaukee, WI 53201, USA Subscriptions TABLE OF CONTENTS To request your FREE subscription to the Pd–N-Heterocyclic Carbene (NHC) Catalysts for Cross-Coupling Reactions ...................................97 Aldrichimica Acta, please contact us by: Eric Assen B. Kantchev, Christopher J. O‘Brien, and Michael G. Organ,* York University, Toronto, Canada Phone: 800-325-3010 (USA) Mail: Attn: Mailroom Aldrich Chemical Co., Inc. ABOUT OUR COVER Sigma-Aldrich Corporation P.O. Box 355 No one will be surprised to read that Milwaukee, WI 53201-9358 the painting on our cover, Ships Riding on the Seine at Rouen (1872/1873, Email: [email protected] oil on canvas, 37.8 × 46.6 cm), was International customers, please contact your local painted by the archetypal Impressionist, Sigma-Aldrich office. For worldwide contact infor- Claude Monet (French, 1840–1926). His distinctive style is recognizable, mation, please see the inside back cover. fresh, and still sought after over 130 The Aldrichimica Acta is also available on the years after his radical and expressive brushwork shocked the art world in Internet at sigma-aldrich.com. Paris in the 1860s and 1870s. Aldrich brand products are sold through Sigma- Monet’s devotion to the ideals of Impressionism lasted throughout his Aldrich, Inc. Sigma-Aldrich, Inc. warrants that its long and prolific life. It is fitting that the Photograph © Board of Trustees, National Gallery of Art, Washington. products conform to the information contained in word Impressionism, which defines the this and other Sigma-Aldrich publications. Purchaser movement and style, was coined by an must determine the suitability of the product for its art critic reviewing Monet’s painting Impression: Sunrise, 1872 (Musée Marmottan, Paris). particular use. See reverse side of invoice or packing slip for additional terms and conditions of sale. This delightful, small painting displays large and small sailboats comfortably resting on the river Seine on a sunny, warm, and idyllic day. Monet’s choice of primarily soft blues and greens creates an alluring calm and relaxed atmosphere. He characteristically captures the illusion of moving water by suggesting with broad brushstrokes that the landscape, sky, clouds, and boats are reflected in the gently rolling water. Aldrichimica Acta (ISSN 0002–5100) is a publication of Aldrich. Aldrich is a member of the Sigma-Aldrich Group. © 2006 Sigma-Aldrich Co. This painting is in the Ailsa Mellon Bruce Collection of Small French Paintings at the National Gallery of Art, Washington, DC. VOL. 39, NO. 4 • 2006 Relax and Enjoy Your Research! Access 40,000+ products with one click. he success of your research relies heavily on having the best products for your Texperiments.