Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Reagents and conditions: (a) 18 + (COCl)2 (1.1 mol equiv), dimethyl formamide (cat.), CH2Cl2, rt, 15 h, concentrate and add to 17, Hunig’s base (2 mol equiv), CH2Cl2, rt, 20 h (75%). (b) (i) dimethyl sulfoxide (2.2 mol equiv), CH2Cl2, −78 °C, add (COCl)2 (1.1 mol equiv), stir 15 min; (ii) add 19, stir 15 min; (iii) add triethylamine (5 mol equiv) and warm to rt 90 min; (iv) 20 in CH2Cl2, sodium triacetoxyborohydride (2 mol equiv), rt (27%).
