Synlett 2003(11): 1713-1715
DOI: 10.1055/s-2003-41012
LETTER
© Georg ThiemeVerlag Stuttgart ˙ New York

Carbonyl Allenylations andPropargylations by 3-Chloro-1-propyne or 2-Propynyl Mesylateswith Tin(IV) Chloride and Tetrabutylammonium Iodide

Yoshiro Masuyama*, Akiko Watabe, Yasuhiko Kurusu
Department of Chemistry, Faculty of Scienceand Technology, Sophia University, 7-1 Kioicho, Chiyoda-ku, Tokyo 102-8554, Japan
Fax: +81(3)32383361; e-Mail: y-masuya@sophia.ac.jp;
Further Information

Publication History

Received 19 June 2003
Publication Date:
11 August 2003 (online)

Abstract

By the use of tin(IV) chloride and tetrabutylammonium iodidein dichloromethane, 3-chloro-1-propyne or 2-propynyl mesylate canbe applied to allenylation and propargylation of aldehydes (carbonylallenylation and propargylation) to produce a mixture of 1-substituted2,3-butadien-1-ols and 1-substituted 3-butyn-1-ols. 1-Substituted2-propynyl mesylates selectively cause carbonyl propargylation,while 3-substituted 2-propynyl mesylates cause carbonyl allenylation.

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A typical procedure is as follows:To the solution of 1a (2 mmol), benzaldehyde(1 mmol) and TBAI (6 mmol) in CH2Cl2 (2 mL)was added drop by drop a one-molar CH2Cl2 solutionof tin(IV) chloride (2 mL) on an ice-bath for 15 min, and then thesolution was stirred at r.t. for 24 h. The solution was dilutedwith 120 mL of a mixed solvent (Et2O: CH2Cl2 = 2:1)and washed successively with aq 10% HCl solution (20 mL),aq NaHCO3 solution (20 mL), H2O (20 mL), andbrine (20 mL). The extracts were dried over anhyd MgSO4.After evaporation of solvent, purification by column chromatography(silica gel, hexane:EtOAc = 10: 1) andthen HPLC (Japan Analytical Industry Co. Ltd., LC-908; JAIGEL-2H;chloroform) afforded 124 mg (85%) of a mixture (2:3 = 60:40)of 1-phenyl-2,3-butadien-1-ol (2; R1, R2 = H,R3 = Ph) and 1-phenyl-3-butyn-1-ol(3; R1, R2 = H, R3 = Ph)as a colorless oil. R f = 0.33(silica gel, hexane:EtOAc = 3: 1). IR(neat):3300, 3060, 3030, 2910, 2150, 1960, 1600, 1540, 1490, 1450, 1390,1190, 1160, 1030, 910, 860, 760, 700, 640 cm-1.Compound 2: 1H NMR (500MHz, CDCl3): δ = 2.11 (d, J = 3.5 Hz,1 H), 4.90-4.98 (m, 2 H), 5.26-5.31 (br, 1 H),5.45 (q, J = 6.5Hz, 1 H), 7.27-7.45 (m, 5 H). Compound 3: 1HNMR (500 MHz, CDCl3): δ = 2.08(t, J = 2.5Hz, 1 H), 2.35 (d, J = 3.0Hz, 1 H), 2.63 (ddd, J = 11, 2.5, 1.0 Hz,1 H), 2.67 (dd, J = 11, 2.5 Hz, 1 H),4.86-4.91 (m, 1 H), 7.27-7.45 (m, 5 H).